diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index d5d32caa3ea0..b21b649b079a 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -7903,6 +7903,12 @@
      {}
     ]
    ], 
+   "css/css-overscroll-behavior/overscrollBehavior-manual.html": [
+    [
+     "/css/css-overscroll-behavior/overscrollBehavior-manual.html", 
+     {}
+    ]
+   ], 
    "css/css-page/forced-page-breaks-002.xht": [
     [
      "/css/css-page/forced-page-breaks-002.xht", 
@@ -10555,12 +10561,6 @@
      {}
     ]
    ], 
-   "css/cssom-view/overscrollBehavior-manual.html": [
-    [
-     "/css/cssom-view/overscrollBehavior-manual.html", 
-     {}
-    ]
-   ], 
    "css/selectors/focus-visible-001-manual.html": [
     [
      "/css/selectors/focus-visible-001-manual.html", 
@@ -130449,6 +130449,150 @@
      {}
     ]
    ], 
+   "css/css-position/static-position/htb-ltr-ltr.html": [
+    [
+     "/css/css-position/static-position/htb-ltr-ltr.html", 
+     [
+      [
+       "/css/css-position/static-position/htb-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/htb-ltr-rtl.tentative.html": [
+    [
+     "/css/css-position/static-position/htb-ltr-rtl.tentative.html", 
+     [
+      [
+       "/css/css-position/static-position/htb-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/htb-rtl-ltr.tentative.html": [
+    [
+     "/css/css-position/static-position/htb-rtl-ltr.tentative.html", 
+     [
+      [
+       "/css/css-position/static-position/htb-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/htb-rtl-rtl.html": [
+    [
+     "/css/css-position/static-position/htb-rtl-rtl.html", 
+     [
+      [
+       "/css/css-position/static-position/htb-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vlr-ltr-ltr.html": [
+    [
+     "/css/css-position/static-position/vlr-ltr-ltr.html", 
+     [
+      [
+       "/css/css-position/static-position/vlr-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vlr-ltr-rtl.tentative.html": [
+    [
+     "/css/css-position/static-position/vlr-ltr-rtl.tentative.html", 
+     [
+      [
+       "/css/css-position/static-position/vlr-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vlr-rtl-ltr.tentative.html": [
+    [
+     "/css/css-position/static-position/vlr-rtl-ltr.tentative.html", 
+     [
+      [
+       "/css/css-position/static-position/vlr-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vlr-rtl-rtl.html": [
+    [
+     "/css/css-position/static-position/vlr-rtl-rtl.html", 
+     [
+      [
+       "/css/css-position/static-position/vlr-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vrl-ltr-ltr.html": [
+    [
+     "/css/css-position/static-position/vrl-ltr-ltr.html", 
+     [
+      [
+       "/css/css-position/static-position/vrl-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vrl-ltr-rtl.tentative.html": [
+    [
+     "/css/css-position/static-position/vrl-ltr-rtl.tentative.html", 
+     [
+      [
+       "/css/css-position/static-position/vrl-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vrl-rtl-ltr.tentative.html": [
+    [
+     "/css/css-position/static-position/vrl-rtl-ltr.tentative.html", 
+     [
+      [
+       "/css/css-position/static-position/vrl-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vrl-rtl-rtl.html": [
+    [
+     "/css/css-position/static-position/vrl-rtl-rtl.html", 
+     [
+      [
+       "/css/css-position/static-position/vrl-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
    "css/css-pseudo/first-letter-001.html": [
     [
      "/css/css-pseudo/first-letter-001.html", 
@@ -168165,6 +168309,18 @@
      {}
     ]
    ], 
+   "css/filter-effects/backdrop-filter-basic-opacity-2.html": [
+    [
+     "/css/filter-effects/backdrop-filter-basic-opacity-2.html", 
+     [
+      [
+       "/css/filter-effects/backdrop-filter-basic-opacity-2-ref.html", 
+       "=="
+      ]
+     ], 
+     {}
+    ]
+   ], 
    "css/filter-effects/backdrop-filter-basic-opacity.html": [
     [
      "/css/filter-effects/backdrop-filter-basic-opacity.html", 
@@ -168206,7 +168362,7 @@
      "/css/filter-effects/backdrop-filter-clip-rect.html", 
      [
       [
-       "/css/filter-effects/backdrop-filter-paint-order-ref.html", 
+       "/css/filter-effects/backdrop-filter-clip-rect-ref.html", 
        "=="
       ]
      ], 
@@ -264918,6 +265074,21 @@
      {}
     ]
    ], 
+   "css/css-position/static-position/htb-ref.html": [
+    [
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vlr-ref.html": [
+    [
+     {}
+    ]
+   ], 
+   "css/css-position/static-position/vrl-ref.html": [
+    [
+     {}
+    ]
+   ], 
    "css/css-properties-values-api/META.yml": [
     [
      {}
@@ -276368,6 +276539,11 @@
      {}
     ]
    ], 
+   "css/filter-effects/backdrop-filter-basic-opacity-2-ref.html": [
+    [
+     {}
+    ]
+   ], 
    "css/filter-effects/backdrop-filter-basic-opacity-ref.html": [
     [
      {}
@@ -298803,6 +298979,11 @@
      {}
     ]
    ], 
+   "media-source/mp4/invalid-codec.mp4": [
+    [
+     {}
+    ]
+   ], 
    "media-source/mp4/test-a-128k-44100Hz-1ch-manifest.json": [
     [
      {}
@@ -298908,6 +299089,11 @@
      {}
     ]
    ], 
+   "media-source/webm/invalid-codec.webm": [
+    [
+     {}
+    ]
+   ], 
    "media-source/webm/test-a-128k-44100Hz-1ch-manifest.json": [
     [
      {}
@@ -304638,12 +304824,12 @@
      {}
     ]
    ], 
-   "resources/chromium/mojo_layouttest_test.mojom.js": [
+   "resources/chromium/mojo_web_test_helper_test.mojom.js": [
     [
      {}
     ]
    ], 
-   "resources/chromium/mojo_layouttest_test.mojom.js.headers": [
+   "resources/chromium/mojo_web_test_helper_test.mojom.js.headers": [
     [
      {}
     ]
@@ -306248,6 +306434,11 @@
      {}
     ]
    ], 
+   "scroll-animations/resources/scrolltimeline-utils.js": [
+    [
+     {}
+    ]
+   ], 
    "secure-contexts/META.yml": [
     [
      {}
@@ -309703,6 +309894,11 @@
      {}
     ]
    ], 
+   "svg/interact/scripted/resources/blank.htm": [
+    [
+     {}
+    ]
+   ], 
    "svg/linking/reftests/href-a-element-ref.html": [
     [
      {}
@@ -334921,6 +335117,12 @@
      {}
     ]
    ], 
+   "content-security-policy/navigation/to-javascript-parent-initiated-parent-csp-disallow.html": [
+    [
+     "/content-security-policy/navigation/to-javascript-parent-initiated-parent-csp-disallow.html", 
+     {}
+    ]
+   ], 
    "content-security-policy/navigation/to-javascript-parent-initiated-parent-csp.html": [
     [
      "/content-security-policy/navigation/to-javascript-parent-initiated-parent-csp.html", 
@@ -379457,6 +379659,12 @@
      {}
     ]
    ], 
+   "media-source/mediasource-invalid-codec.html": [
+    [
+     "/media-source/mediasource-invalid-codec.html", 
+     {}
+    ]
+   ], 
    "media-source/mediasource-is-type-supported.html": [
     [
      "/media-source/mediasource-is-type-supported.html", 
@@ -404499,6 +404707,12 @@
      {}
     ]
    ], 
+   "scroll-animations/current-time.html": [
+    [
+     "/scroll-animations/current-time.html", 
+     {}
+    ]
+   ], 
    "scroll-animations/idlharness.window.js": [
     [
      "/scroll-animations/idlharness.window.html", 
@@ -408491,6 +408705,30 @@
      {}
     ]
    ], 
+   "svg/interact/scripted/composed.window.svg": [
+    [
+     "/svg/interact/scripted/composed.window.svg", 
+     {}
+    ]
+   ], 
+   "svg/interact/scripted/focus-events.svg": [
+    [
+     "/svg/interact/scripted/focus-events.svg", 
+     {}
+    ]
+   ], 
+   "svg/interact/scripted/focus-tabindex-default-value.svg": [
+    [
+     "/svg/interact/scripted/focus-tabindex-default-value.svg", 
+     {}
+    ]
+   ], 
+   "svg/interact/scripted/tabindex-focus-flag.svg": [
+    [
+     "/svg/interact/scripted/tabindex-focus-flag.svg", 
+     {}
+    ]
+   ], 
    "svg/linking/scripted/a-download-click.svg": [
     [
      "/svg/linking/scripted/a-download-click.svg", 
@@ -414329,6 +414567,14 @@
      {}
     ]
    ], 
+   "webrtc/legacy/RTCPeerConnection-addStream.https.html": [
+    [
+     "/webrtc/legacy/RTCPeerConnection-addStream.https.html", 
+     {
+      "timeout": "long"
+     }
+    ]
+   ], 
    "webrtc/legacy/RTCPeerConnection-createOffer-offerToReceive.html": [
     [
      "/webrtc/legacy/RTCPeerConnection-createOffer-offerToReceive.html", 
@@ -441979,7 +442225,7 @@
    "support"
   ], 
   ".taskcluster.yml": [
-   "5e67f71ed89c0dafbcf6cab647a9fad339253314", 
+   "4a6de3b5b177a41dd2f5b7318a837e5e4eae54a8", 
    "support"
   ], 
   ".travis.yml": [
@@ -446727,7 +446973,7 @@
    "testharness"
   ], 
   "IndexedDB/idb-explicit-commit.any.js": [
-   "b2dec751b1a8f1e82fce2db965b78f26d416073e", 
+   "da4bd8c95269d6f0630d77ba4922a8251f7c18e6", 
    "testharness"
   ], 
   "IndexedDB/idb_binary_key_conversion.htm": [
@@ -452499,7 +452745,7 @@
    "testharness"
   ], 
   "bluetooth/resources/bluetooth-helpers.js": [
-   "9b23d650baf2a77c105f61df2d8f197812aefce0", 
+   "c4e26077c34283cc6d442cc8bc57f799eadd5a99", 
    "support"
   ], 
   "bluetooth/resources/health-thermometer-iframe.html": [
@@ -472226,6 +472472,10 @@
    "d2289257a888efe0f35e296922948bdbf5f70394", 
    "testharness"
   ], 
+  "content-security-policy/navigation/to-javascript-parent-initiated-parent-csp-disallow.html": [
+   "3a0641170ea26edfd998acc9105ccc3bad8b4f98", 
+   "testharness"
+  ], 
   "content-security-policy/navigation/to-javascript-parent-initiated-parent-csp.html": [
    "4cbb37ee68fb83890d5f4881c4e1a78f013eaa52", 
    "testharness"
@@ -561542,6 +561792,10 @@
    "e49fa49bc4e26572a68ad947e8e82a63ee46d4e2", 
    "testharness"
   ], 
+  "css/css-overscroll-behavior/overscrollBehavior-manual.html": [
+   "97f52984a51ae4157ec8ed91ddf4b3b8d405bec6", 
+   "manual"
+  ], 
   "css/css-page/META.yml": [
    "2f9e29e2787e8c41d0a9ebe1df8342a6c52a01a8", 
    "support"
@@ -562734,6 +562988,66 @@
    "969cededcbe658a8d25c0cf9cabb97d86d965a77", 
    "support"
   ], 
+  "css/css-position/static-position/htb-ltr-ltr.html": [
+   "770ce7bd8a3b49291d741e85bed17d8aa0619334", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/htb-ltr-rtl.tentative.html": [
+   "abc8585ab24d4455a3053a75d8518bd6547d2175", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/htb-ref.html": [
+   "bd534b07729131a7e253c8647bf12ce8e04b7fc8", 
+   "support"
+  ], 
+  "css/css-position/static-position/htb-rtl-ltr.tentative.html": [
+   "6a20341cbc6330ddc0e41436597f52d67f147ec3", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/htb-rtl-rtl.html": [
+   "279754ca4ea2102b8fd84b3225495f2a17816a08", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vlr-ltr-ltr.html": [
+   "1d95b46a0ff039ebd37b5de429ef755029d3cb79", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vlr-ltr-rtl.tentative.html": [
+   "d3faab1430442454472b0c085cd20903e406fb88", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vlr-ref.html": [
+   "2dc2012f0466c4cd2fd8f3d98da3a6e52af90070", 
+   "support"
+  ], 
+  "css/css-position/static-position/vlr-rtl-ltr.tentative.html": [
+   "736339ab54e55692780b78f50854b768b09feecd", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vlr-rtl-rtl.html": [
+   "71f810fc7db38c10a6fe52911303592e77d5c8bd", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vrl-ltr-ltr.html": [
+   "d9e613a9eade04db2b6f66cc3ff3bf749f78859f", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vrl-ltr-rtl.tentative.html": [
+   "342d1cadfd1492baaea7080322ff089b025bf22e", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vrl-ref.html": [
+   "31be2b52cd982bc696b0377b60461870ffcc0b58", 
+   "support"
+  ], 
+  "css/css-position/static-position/vrl-rtl-ltr.tentative.html": [
+   "b0960490cfc20871ca1dce12b5c75d54c80883c3", 
+   "reftest"
+  ], 
+  "css/css-position/static-position/vrl-rtl-rtl.html": [
+   "8bdb06c8271e89cfed18bae3eff5b413fc46f46f", 
+   "reftest"
+  ], 
   "css/css-properties-values-api/META.yml": [
    "38cd166ca8f45769c269039577aac391ad707e75", 
    "support"
@@ -590606,10 +590920,6 @@
    "772cc34f05bffc5b8445cd23ba13d9357269b84b", 
    "reftest"
   ], 
-  "css/cssom-view/overscrollBehavior-manual.html": [
-   "d66317fe306d264708c3cac725d562c22034a5f6", 
-   "manual"
-  ], 
   "css/cssom-view/resources/elementsFromPoint.js": [
    "ba986ef3f568d4971eb4e84c4faaeae6e276b975", 
    "support"
@@ -591527,11 +591837,19 @@
    "support"
   ], 
   "css/filter-effects/backdrop-filter-basic-background-color-ref.html": [
-   "44dd8d44d64c1d89d09a2a35b76c86acfff87d51", 
+   "a3dbad0b497d0ab7eaab494178fa87be78cf0d3c", 
    "support"
   ], 
   "css/filter-effects/backdrop-filter-basic-background-color.html": [
-   "39febb17d2df21456b8f8ea4a42407e799a6eb2b", 
+   "c48cadeef67a026d8b63a286da05ce864e1f4604", 
+   "reftest"
+  ], 
+  "css/filter-effects/backdrop-filter-basic-opacity-2-ref.html": [
+   "1027811f261a9c8ed7f33bf9e0efc42b1706aa93", 
+   "support"
+  ], 
+  "css/filter-effects/backdrop-filter-basic-opacity-2.html": [
+   "8d7df67fbedb09dd5980b7db083bca93249157eb", 
    "reftest"
   ], 
   "css/filter-effects/backdrop-filter-basic-opacity-ref.html": [
@@ -591563,15 +591881,15 @@
    "support"
   ], 
   "css/filter-effects/backdrop-filter-clip-rect.html": [
-   "8b5d9f4e34f8f4fd04c988f99f03685c3fbf58c9", 
+   "075b34d513c2959f5dbc40c316d7a13330cfd262", 
    "reftest"
   ], 
   "css/filter-effects/backdrop-filter-edge-pixels-ref.html": [
-   "1960435775c24f7b7464e1f42cd9da15766c2b5e", 
+   "bbd562856f7a0ee305874575935c66e8b4830c1d", 
    "support"
   ], 
   "css/filter-effects/backdrop-filter-edge-pixels.html": [
-   "1e29d725ebcd8d78350ba2a2fcff50b3b239f88a", 
+   "c26e70ce918c4a43609afd2ce61b320bbc782309", 
    "reftest"
   ], 
   "css/filter-effects/backdrop-filter-fixed-clip-ref.html": [
@@ -591583,19 +591901,19 @@
    "reftest"
   ], 
   "css/filter-effects/backdrop-filter-isolation-fixed.html": [
-   "c812d1f67436fd91fbb3ddfc5d3f147d8f265baa", 
+   "a3c3fa25a85077b8297feae745d2ab5cd9e24b23", 
    "reftest"
   ], 
   "css/filter-effects/backdrop-filter-isolation-isolate.html": [
-   "99fa69d03fa6fac067a375a951ccb292183dc8df", 
+   "88dd91ac8fe3c033a999315b342cbe82a482721f", 
    "reftest"
   ], 
   "css/filter-effects/backdrop-filter-isolation-ref.html": [
-   "58f5a7ec1edc11d59c2ef789bf078bace7dceb71", 
+   "470704a688f3883aee6a3fb6be21be1591007f75", 
    "support"
   ], 
   "css/filter-effects/backdrop-filter-isolation.html": [
-   "e41772578e5d2ccea955bb9f65cfa77771a36027", 
+   "500228df08162d4a946058e2252d225209a6d4e1", 
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   "css/filter-effects/backdrop-filter-paint-order-ref.html": [
@@ -632123,7 +632441,7 @@
    "support"
   ], 
   "interfaces/event-timing.idl": [
-   "0e12737bcc6e75d643abdd0e6bc44d44bcd8e6af", 
+   "cd727beead3741c6cd2b280d180e4913991d7d1c", 
    "support"
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   "interfaces/feature-policy.idl": [
@@ -632427,7 +632745,7 @@
    "support"
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   "interfaces/web-nfc.idl": [
-   "d54773be499366806bbd93c7fc119ff7a3a2ff72", 
+   "3dd4817eb0dfb329720b0e6da5097bf2d28cc6b4", 
    "support"
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   "interfaces/web-share.idl": [
@@ -633622,6 +633940,10 @@
    "f92fdbc3c71eb1caeb8c49b40be29d64434687c6", 
    "testharness"
   ], 
+  "media-source/mediasource-invalid-codec.html": [
+   "19aa00c4d5f4966ef8a5de657341141f69c08ea3", 
+   "testharness"
+  ], 
   "media-source/mediasource-is-type-supported.html": [
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    "testharness"
@@ -633710,6 +634032,10 @@
    "bd202919899c5586a62790a11780649642447066", 
    "support"
   ], 
+  "media-source/mp4/invalid-codec.mp4": [
+   "6fcc7c21a698ab9d9622c4a6fb6685aeafdd6f40", 
+   "support"
+  ], 
   "media-source/mp4/test-a-128k-44100Hz-1ch-manifest.json": [
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    "support"
@@ -633794,6 +634120,10 @@
    "1b0e7b56a6b74b4c1636c80911741cbb565d0397", 
    "support"
   ], 
+  "media-source/webm/invalid-codec.webm": [
+   "f1c8bdd7abba1f6b24dc0a5d44463c3bda770d0d", 
+   "support"
+  ], 
   "media-source/webm/test-a-128k-44100Hz-1ch-manifest.json": [
    "524da8149fe6d36c891501d059f85621f06cde36", 
    "support"
@@ -655606,11 +655936,11 @@
    "6805c323df5a975231648b830e33ce183c3cbbd3", 
    "support"
   ], 
-  "resources/chromium/mojo_layouttest_test.mojom.js": [
-   "babaeda156fc8c10afcc08c6652576e32a6741e1", 
+  "resources/chromium/mojo_web_test_helper_test.mojom.js": [
+   "cfbad086898778b920c2d750890c870e082dc60a", 
    "support"
   ], 
-  "resources/chromium/mojo_layouttest_test.mojom.js.headers": [
+  "resources/chromium/mojo_web_test_helper_test.mojom.js.headers": [
    "6805c323df5a975231648b830e33ce183c3cbbd3", 
    "support"
   ], 
@@ -655759,7 +656089,7 @@
    "support"
   ], 
   "resources/test/tests/functional/api-tests-1.html": [
-   "49f962a60c7b045f38e11b4a3c4ecd624b52ce6f", 
+   "1c108c5a638bb01f8ed8e6d4b72f1557dda8645d", 
    "support"
   ], 
   "resources/test/tests/functional/api-tests-2.html": [
@@ -656031,7 +656361,7 @@
    "support"
   ], 
   "resources/testharness.js": [
-   "2e14c30730d2efaf8fab98328f0a07d270627802", 
+   "b08074b96bd64acdec4b0aaead9cf957aa725e85", 
    "support"
   ], 
   "resources/testharness.js.headers": [
@@ -656946,10 +657276,18 @@
    "a449b32d2be4bfe9e825ff3b3637a5ddb609b93e", 
    "testharness"
   ], 
+  "scroll-animations/current-time.html": [
+   "8c70594612ac758f7934d8f30818cb0150925e5e", 
+   "testharness"
+  ], 
   "scroll-animations/idlharness.window.js": [
    "90157580ce00716403346f369b1e25bba8db23c2", 
    "testharness"
   ], 
+  "scroll-animations/resources/scrolltimeline-utils.js": [
+   "b0e5ead25c6ecd72bb0afcba572af46b819152aa", 
+   "support"
+  ], 
   "secure-contexts/META.yml": [
    "e6537166280091c062a8894508f3f0ab9a33a8bf", 
    "support"
@@ -658575,7 +658913,7 @@
    "testharness"
   ], 
   "service-workers/service-worker/fetch-request-css-base-url.https.html": [
-   "7feccfb98c56fa29eae0c204791ec90e67e5dd5c", 
+   "a08e0c74881364f7fd29d3e6ac332a7e1d94bf7a", 
    "testharness"
   ], 
   "service-workers/service-worker/fetch-request-css-cross-origin.https.html": [
@@ -659395,7 +659733,7 @@
    "support"
   ], 
   "service-workers/service-worker/resources/fetch-request-css-base-url-iframe.html": [
-   "0edf2e7f9659a5ba2b204c76ec04503eacac14a7", 
+   "504e10435642330fbeb2334855bb9d3966276469", 
    "support"
   ], 
   "service-workers/service-worker/resources/fetch-request-css-base-url-style.css": [
@@ -659403,7 +659741,7 @@
    "support"
   ], 
   "service-workers/service-worker/resources/fetch-request-css-base-url-worker.js": [
-   "91c325998a3b8d6a6106a834903e20559e0f0055", 
+   "e8dbd2725c68f9326c41ae5e7bde65158970a272", 
    "support"
   ], 
   "service-workers/service-worker/resources/fetch-request-css-cross-origin-mime-check-cross.css": [
@@ -664118,6 +664456,26 @@
    "94836f7c0331cb8a1caebacef02a75018b2b4ddb", 
    "testharness"
   ], 
+  "svg/interact/scripted/composed.window.svg": [
+   "b63dcf024439446e0624f98cfa9f7ceb01544524", 
+   "testharness"
+  ], 
+  "svg/interact/scripted/focus-events.svg": [
+   "bf307b79fdf10c578d93332f57d4de2ab844eb34", 
+   "testharness"
+  ], 
+  "svg/interact/scripted/focus-tabindex-default-value.svg": [
+   "3af1acffd8de01618fb1dc9e8a753bcbb0357f1c", 
+   "testharness"
+  ], 
+  "svg/interact/scripted/resources/blank.htm": [
+   "18ecdcb795c33d6ab7bbb43f647947defca5634d", 
+   "support"
+  ], 
+  "svg/interact/scripted/tabindex-focus-flag.svg": [
+   "29ba209b2badecaac695a678540cc53e5c4ed3f5", 
+   "testharness"
+  ], 
   "svg/linking/reftests/href-a-element-attr-change.html": [
    "c74b2e015613a09d1cecb5a0c3136d26f07e2a5b", 
    "reftest"
@@ -677287,7 +677645,7 @@
    "testharness"
   ], 
   "webrtc/RTCPeerConnection-track-stats.https.html": [
-   "9ad679272b57e4d77ed4d2ceea3c1283e2e0eacd", 
+   "30c368f670d78154fd3ca3c67d20eb67d9a052e7", 
    "testharness"
   ], 
   "webrtc/RTCPeerConnection-transceivers.https.html": [
@@ -677311,7 +677669,7 @@
    "testharness"
   ], 
   "webrtc/RTCRtpParameters-encodings.html": [
-   "b446dde230efbbdb197c7f24f16e2490271563c4", 
+   "b8ae4e4c187ce0ccea70421a248c900aae844af6", 
    "testharness"
   ], 
   "webrtc/RTCRtpParameters-headerExtensions.html": [
@@ -677319,7 +677677,7 @@
    "testharness"
   ], 
   "webrtc/RTCRtpParameters-helper.js": [
-   "c4105decdfcb12286d4b153ab07f7be25baf1aad", 
+   "8f7c85df475f5a5c6cf09cfa08d0b9c45c1e7546", 
    "support"
   ], 
   "webrtc/RTCRtpParameters-rtcp.html": [
@@ -677430,6 +677788,10 @@
    "8adbf6aa173949718a90bd54cc95361e1a8801ba", 
    "support"
   ], 
+  "webrtc/legacy/RTCPeerConnection-addStream.https.html": [
+   "5a35ebc53b8d7ce3857d4869a476e0e99a9078c8", 
+   "testharness"
+  ], 
   "webrtc/legacy/RTCPeerConnection-createOffer-offerToReceive.html": [
    "f710498e75f1be587c66d1d0dfe215cb136cc747", 
    "testharness"
@@ -677443,7 +677805,7 @@
    "testharness"
   ], 
   "webrtc/no-media-call.html": [
-   "0f2e2a33e62b47292085c14ad36a253d800c5982", 
+   "10933fae4c396198ade091894ea8538d1a174eaf", 
    "testharness"
   ], 
   "webrtc/promises-call.html": [
diff --git a/tests/wpt/metadata/css/filter-effects/backdrop-filter-basic-opacity-2.html.ini b/tests/wpt/metadata/css/filter-effects/backdrop-filter-basic-opacity-2.html.ini
new file mode 100644
index 000000000000..1e7eb79fb1bc
--- /dev/null
+++ b/tests/wpt/metadata/css/filter-effects/backdrop-filter-basic-opacity-2.html.ini
@@ -0,0 +1,2 @@
+[backdrop-filter-basic-opacity-2.html]
+  expected: FAIL
diff --git a/tests/wpt/metadata/css/filter-effects/backdrop-filter-clip-rect.html.ini b/tests/wpt/metadata/css/filter-effects/backdrop-filter-clip-rect.html.ini
deleted file mode 100644
index 3a98309a68b8..000000000000
--- a/tests/wpt/metadata/css/filter-effects/backdrop-filter-clip-rect.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[backdrop-filter-clip-rect.html]
-  expected: FAIL
diff --git a/tests/wpt/metadata/encoding/single-byte-decoder.html.ini b/tests/wpt/metadata/encoding/single-byte-decoder.html.ini
index 7babafb1e4aa..b44b97c27dd5 100644
--- a/tests/wpt/metadata/encoding/single-byte-decoder.html.ini
+++ b/tests/wpt/metadata/encoding/single-byte-decoder.html.ini
@@ -549,9 +549,6 @@
   [windows-1254: iso88599 (XMLHttpRequest)]
     expected: TIMEOUT
 
-  [windows-1254: iso-8859-9 (XMLHttpRequest)]
-    expected: TIMEOUT
-
   [windows-1258: x-cp1258 (XMLHttpRequest)]
     expected: TIMEOUT
 
@@ -564,9 +561,6 @@
   [x-mac-cyrillic: x-mac-ukrainian (XMLHttpRequest)]
     expected: TIMEOUT
 
-  [windows-1254: csisolatin5 (XMLHttpRequest)]
-    expected: TIMEOUT
-
   [windows-1257: cp1257 (XMLHttpRequest)]
     expected: TIMEOUT
 
@@ -576,9 +570,6 @@
   [windows-1257: x-cp1257 (XMLHttpRequest)]
     expected: TIMEOUT
 
-  [windows-1253: windows-1253 (XMLHttpRequest)]
-    expected: TIMEOUT
-
   [windows-1254: l5 (XMLHttpRequest)]
     expected: TIMEOUT
 
@@ -612,23 +603,5 @@
   [windows-1254: iso8859-9 (XMLHttpRequest)]
     expected: TIMEOUT
 
-  [windows-1253: x-cp1253 (XMLHttpRequest)]
-    expected: TIMEOUT
-
-  [windows-1254: cp1254 (XMLHttpRequest)]
-    expected: TIMEOUT
-
-  [windows-1253: cp1253 (XMLHttpRequest)]
-    expected: TIMEOUT
-
-  [windows-1252: x-cp1252 (XMLHttpRequest)]
-    expected: TIMEOUT
-
-  [windows-1252: windows-1252 (XMLHttpRequest)]
-    expected: TIMEOUT
-
-  [windows-1252: us-ascii (XMLHttpRequest)]
-    expected: TIMEOUT
-
 
 [single-byte-decoder.html?TextDecoder]
diff --git a/tests/wpt/metadata/html/browsers/browsing-the-web/navigating-across-documents/006.html.ini b/tests/wpt/metadata/html/browsers/browsing-the-web/navigating-across-documents/006.html.ini
deleted file mode 100644
index c85443610681..000000000000
--- a/tests/wpt/metadata/html/browsers/browsing-the-web/navigating-across-documents/006.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[006.html]
-  [Link with onclick form submit and href navigation ]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
deleted file mode 100644
index 87b07c3e6704..000000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_1.html]
-  [Multiple history traversals from the same task]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
new file mode 100644
index 000000000000..75d75b4cda2e
--- /dev/null
+++ b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
@@ -0,0 +1,4 @@
+[traverse_the_history_2.html]
+  [Multiple history traversals, last would be aborted]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini
index d1f06eba410b..6871a4c3e6d1 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini
@@ -8,7 +8,7 @@
     expected: TIMEOUT
 
   [picture: source (max-width:500px) valid image, img broken image, resize to narrow]
-    expected: FAIL
+    expected: TIMEOUT
 
   [picture: source (max-width:500px) valid image, img valid image, resize to narrow]
     expected: FAIL
@@ -19,3 +19,6 @@
   [picture: same URL in source (max-width:500px) and img, resize to narrow]
     expected: FAIL
 
+  [picture: source (max-width:500px) broken image, img valid image, resize to narrow]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
deleted file mode 100644
index 8cc42056d34e..000000000000
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
+++ /dev/null
@@ -1,10 +0,0 @@
-[non-active-document.html]
-  [DOMParser]
-    expected: FAIL
-
-  [createHTMLDocument]
-    expected: FAIL
-
-  [<template>]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/sizes/parse-a-sizes-attribute-quirks-mode.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/sizes/parse-a-sizes-attribute-quirks-mode.html.ini
index ba527d2f01b1..a0e0184eb464 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/sizes/parse-a-sizes-attribute-quirks-mode.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/sizes/parse-a-sizes-attribute-quirks-mode.html.ini
@@ -1,5 +1,4 @@
 [parse-a-sizes-attribute-quirks-mode.html]
-  expected: TIMEOUT
   [<img srcset="/images/green-1x1.png?e38b 50w, /images/green-16x16.png?e38b 51w" sizes="(min-width:max(-200vw, 0)) 1px"> ref sizes="1px" (quirks mode)]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/interactive-elements/the-details-element/toggleEvent.html.ini b/tests/wpt/metadata/html/semantics/interactive-elements/the-details-element/toggleEvent.html.ini
new file mode 100644
index 000000000000..9e522297c94d
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/interactive-elements/the-details-element/toggleEvent.html.ini
@@ -0,0 +1,7 @@
+[toggleEvent.html]
+  [Calling open twice on 'details' fires only one toggle event]
+    expected: FAIL
+
+  [Setting open=true to opened 'details' element should not fire a toggle event at the 'details' element]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/syntax/parsing/DOMContentLoaded-defer.html.ini b/tests/wpt/metadata/html/syntax/parsing/DOMContentLoaded-defer.html.ini
new file mode 100644
index 000000000000..a9677391662b
--- /dev/null
+++ b/tests/wpt/metadata/html/syntax/parsing/DOMContentLoaded-defer.html.ini
@@ -0,0 +1,4 @@
+[DOMContentLoaded-defer.html]
+  [The end: DOMContentLoaded and defer scripts]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini
index ce482a60da89..c6d49957c4a3 100644
--- a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini
+++ b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini
@@ -2,6 +2,3 @@
   [document.open() after parser is aborted]
     expected: FAIL
 
-  [async document.open() after parser is aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/performance-timeline/webtiming-resolution.any.js.ini b/tests/wpt/metadata/performance-timeline/webtiming-resolution.any.js.ini
index 99a24216c88b..7725b118e9d9 100644
--- a/tests/wpt/metadata/performance-timeline/webtiming-resolution.any.js.ini
+++ b/tests/wpt/metadata/performance-timeline/webtiming-resolution.any.js.ini
@@ -12,3 +12,6 @@
   [Verifies the resolution of entry.startTime is at least 5 microseconds.]
     expected: TIMEOUT
 
+  [Verifies the resolution of performance.now() is at least 5 microseconds.]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/quirks/unitless-length/quirks.html.ini b/tests/wpt/metadata/quirks/unitless-length/no-quirks.html.ini
similarity index 99%
rename from tests/wpt/metadata/quirks/unitless-length/quirks.html.ini
rename to tests/wpt/metadata/quirks/unitless-length/no-quirks.html.ini
index 2ed601c6ff44..818a429ed392 100644
--- a/tests/wpt/metadata/quirks/unitless-length/quirks.html.ini
+++ b/tests/wpt/metadata/quirks/unitless-length/no-quirks.html.ini
@@ -1,4 +1,4 @@
-[quirks.html]
+[no-quirks.html]
   [top: -\\31 .5]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/workers/semantics/multiple-workers/005.html.ini b/tests/wpt/metadata/workers/semantics/multiple-workers/005.html.ini
index 268949ced5ce..f584fce5df19 100644
--- a/tests/wpt/metadata/workers/semantics/multiple-workers/005.html.ini
+++ b/tests/wpt/metadata/workers/semantics/multiple-workers/005.html.ini
@@ -1,4 +1,5 @@
 [005.html]
+  expected: ERROR
   [dedicated worker in shared worker in dedicated worker]
     expected: FAIL
 
diff --git a/tests/wpt/web-platform-tests/.taskcluster.yml b/tests/wpt/web-platform-tests/.taskcluster.yml
index 5e67f71ed89c..4a6de3b5b177 100644
--- a/tests/wpt/web-platform-tests/.taskcluster.yml
+++ b/tests/wpt/web-platform-tests/.taskcluster.yml
@@ -98,15 +98,26 @@ tasks:
           each(browser):
             $map:
               - name: wpt-${browser.name}-${browser.channel}-stability
+                checkout: FETCH_HEAD
+                diff_range: HEAD^
                 description: >-
                   Verify that all tests affected by a pull request are stable
                   when executed in ${browser.name}.
                 extra_args: '--verify'
               - name: wpt-${browser.name}-${browser.channel}-results
+                checkout: FETCH_HEAD
+                diff_range: HEAD^
                 description: >-
                   Collect results for all tests affected by a pull request in
                   ${browser.name}.
                 extra_args: '--no-fail-on-unexpected --log-wptreport=../artifacts/wpt_report.json'
+              - name: wpt-${browser.name}-${browser.channel}-results-without-changes
+                checkout: FETCH_HEAD^
+                diff_range: FETCH_HEAD
+                description: >-
+                  Collect results for all tests affected by a pull request in
+                  ${browser.name} but without the changes in the PR.
+                extra_args: '--no-fail-on-unexpected --log-wptreport=../artifacts/wpt_report.json'
             each(operation):
               taskId: {$eval: 'as_slugid(operation.name)'}
               taskGroupId: {$eval: 'as_slugid("task group")'}
@@ -125,7 +136,7 @@ tasks:
                 owner: ${event.pull_request.user.login}@users.noreply.github.com
                 source: ${event.repository.url}
               payload:
-                image: hexcles/web-platform-tests:0.23
+                image: harjgam/web-platform-tests:0.25
                 maxRunTime: 7200
                 artifacts:
                   public/results:
@@ -145,12 +156,12 @@ tasks:
                     ~/start.sh
                       ${event.repository.clone_url}
                       refs/pull/${event.number}/merge
-                      FETCH_HEAD
+                      ${operation.checkout}
                       ${browser.name}
                       ${browser.channel};
                     cd ~/web-platform-tests;
                     ./tools/ci/taskcluster-run.py
-                      --commit-range HEAD^
+                      --commit-range ${operation.diff_range}
                       ${browser.name}
                       --
                       --channel=${browser.channel}
diff --git a/tests/wpt/web-platform-tests/IndexedDB/idb-explicit-commit.any.js b/tests/wpt/web-platform-tests/IndexedDB/idb-explicit-commit.any.js
index b2dec751b1a8..da4bd8c95269 100644
--- a/tests/wpt/web-platform-tests/IndexedDB/idb-explicit-commit.any.js
+++ b/tests/wpt/web-platform-tests/IndexedDB/idb-explicit-commit.any.js
@@ -8,8 +8,8 @@
  */
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -43,7 +43,7 @@ promise_test(async testCase => {
 
   // Upgrade the versionDB database and explicitly commit its versionchange
   // transaction.
-  db = await migrateDatabase(testCase, 2, async (db, txn) => {
+  db = await migrateDatabase(testCase, 2, (db, txn) => {
     txn.commit();
   });
   assert_equals(2, db.version,
@@ -55,8 +55,8 @@ promise_test(async testCase => {
 
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -69,8 +69,8 @@ promise_test(async testCase => {
 
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -88,8 +88,8 @@ promise_test(async testCase => {
 
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -110,8 +110,8 @@ promise_test(async testCase => {
 
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -124,8 +124,8 @@ promise_test(async testCase => {
 
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -138,8 +138,8 @@ promise_test(async testCase => {
 
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -162,8 +162,8 @@ promise_test(async testCase => {
 
 
 promise_test(async testCase => {
-  const db = await createDatabase(testCase, async db => {
-    await createBooksStore(testCase, db);
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
   });
   const txn = db.transaction(['books'], 'readwrite');
   const objectStore = txn.objectStore('books');
@@ -179,3 +179,79 @@ promise_test(async testCase => {
   releaseTxnFunction();
   db.close();
 }, 'Calling txn.commit() when txn is inactive should throw.');
+
+
+promise_test(async testCase => {
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
+    createNotBooksStore(testCase, db);
+  });
+  // Txn1 should commit before txn2, even though txn2 uses commit().
+  const txn1 = db.transaction(['books'], 'readwrite');
+  const objectStore1 = txn1.objectStore('books');
+  const putRequest1 = objectStore1.put({isbn:'one', title:'title1'});
+  const releaseTxnFunction = keepAlive(testCase, txn1, 'books');
+
+  const txn2 = db.transaction(['books'], 'readwrite');
+  const objectStore2 = txn2.objectStore('books');
+  const putRequest2 = objectStore2.put({isbn:'one', title:'title2'});
+  txn2.commit();
+
+  // Exercise the IndexedDB transaction ordering by executing one with a
+  // different scope.
+  const txn3 = db.transaction(['not_books'], 'readwrite');
+  const objectStore3 = txn3.objectStore('not_books');
+  objectStore3.put({'title': 'not_title'}, 'key');
+  txn3.oncomplete = function() {
+    releaseTxnFunction();
+  }
+  await Promise.all([promiseForTransaction(testCase, txn1),
+                     promiseForTransaction(testCase, txn2)]);
+
+  // Read the data back to verify that txn2 executed last.
+  const txn4 = db.transaction(['books'], 'readonly');
+  const objectStore4 = txn4.objectStore('books');
+  const getRequest4 = objectStore4.get('one');
+  await promiseForTransaction(testCase, txn4);
+  assert_equals(getRequest4.result.title, 'title2');
+  db.close();
+}, 'Transactions with same scope should stay in program order, even if one '
+   + 'calls commit.');
+
+
+promise_test(async testCase => {
+  const db = await createDatabase(testCase, db => {
+    createBooksStore(testCase, db);
+  });
+  // Txn1 creates the book 'one' so the 'add()' below fails.
+  const txn1 = db.transaction(['books'], 'readwrite');
+  const objectStore1 = txn1.objectStore('books');
+  const putRequest1 = objectStore1.add({isbn:'one', title:'title1'});
+  txn1.commit();
+  await promiseForTransaction(testCase, txn1);
+
+  // Txn2 should abort, because the 'add' call is invalid, and commit() was
+  // called.
+  const txn2 = db.transaction(['books'], 'readwrite');
+  const objectStore2 = txn2.objectStore('books');
+  objectStore2.put({isbn:'two', title:'title2'});
+  const addRequest2 = objectStore2.add({isbn:'one', title:'title2'});
+  txn2.commit();
+  txn2.oncomplete = assert_unreached(
+    'Transaction with invalid "add" call should not be completed.');
+
+  var addWatcher = requestWatcher(testCase, addRequest2);
+  var txnWatcher = transactionWatcher(testCase, txn2);
+  await Promise.all([addWatcher.wait_for('error'),
+                     txnWatcher.wait_for('error', 'abort')]);
+
+  // Read the data back to verify that txn2 was aborted.
+  const txn3 = db.transaction(['books'], 'readonly');
+  const objectStore3 = txn3.objectStore('books');
+  const getRequest1 = objectStore3.get('one');
+  const getRequest2 = objectStore3.count('two');
+  await promiseForTransaction(testCase, txn3);
+  assert_equals(getRequest1.result.title, 'title1');
+  assert_equals(getRequest2.result, 0);
+  db.close();
+}, 'Transactions that explicitly commit and have errors should abort.');
diff --git a/tests/wpt/web-platform-tests/bluetooth/resources/bluetooth-helpers.js b/tests/wpt/web-platform-tests/bluetooth/resources/bluetooth-helpers.js
index 9b23d650baf2..c4e26077c342 100644
--- a/tests/wpt/web-platform-tests/bluetooth/resources/bluetooth-helpers.js
+++ b/tests/wpt/web-platform-tests/bluetooth/resources/bluetooth-helpers.js
@@ -40,7 +40,7 @@ function performChromiumSetup() {
   }
   return loadScripts([
     `${prefix}/mojo_bindings.js`,
-    `${prefix}/mojo_layouttest_test.mojom.js`,
+    `${prefix}/mojo_web_test_helper_test.mojom.js`,
     `${prefix}/uuid.mojom.js`,
     `${prefix}/fake_bluetooth.mojom.js`,
     `${prefix}/fake_bluetooth_chooser.mojom.js`,
diff --git a/tests/wpt/web-platform-tests/content-security-policy/navigation/to-javascript-parent-initiated-parent-csp-disallow.html b/tests/wpt/web-platform-tests/content-security-policy/navigation/to-javascript-parent-initiated-parent-csp-disallow.html
new file mode 100644
index 000000000000..3a0641170ea2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/content-security-policy/navigation/to-javascript-parent-initiated-parent-csp-disallow.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<head>
+<meta http-equiv="content-security-policy" content="script-src 'self' 'nonce-abc'">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<iframe src="support/frame-with-csp.sub.html?csp=script-src%20'self'%20'unsafe-inline'"></iframe>
+<script nonce='abc'>
+  var t = async_test("Should not have executed the javascript url");
+  const iframe = document.querySelector("iframe");
+  iframe.addEventListener('load', () => {
+    window.onmessage = t.step_func(function(e) {
+      if (e.data == "executed")
+        assert_true(false, "Javascript url executed");
+    });
+    window.addEventListener('securitypolicyviolation', t.step_func_done(function(e) {
+      assert_equals(e.blockedURI, 'inline');
+    }));
+    iframe.contentWindow.location.href = 'javascript:parent.postMessage(\'executed\', \'*\')'
+  });
+</script>
+</body>
diff --git a/tests/wpt/web-platform-tests/css/cssom-view/overscrollBehavior-manual.html b/tests/wpt/web-platform-tests/css/css-overscroll-behavior/overscrollBehavior-manual.html
similarity index 98%
rename from tests/wpt/web-platform-tests/css/cssom-view/overscrollBehavior-manual.html
rename to tests/wpt/web-platform-tests/css/css-overscroll-behavior/overscrollBehavior-manual.html
index d66317fe306d..97f52984a51a 100644
--- a/tests/wpt/web-platform-tests/css/cssom-view/overscrollBehavior-manual.html
+++ b/tests/wpt/web-platform-tests/css/css-overscroll-behavior/overscrollBehavior-manual.html
@@ -1,6 +1,7 @@
 <!doctype html>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
+<link rel="help" href="https://drafts.csswg.org/css-overscroll-behavior">
 
 <style>
 .outer {
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ltr-ltr.html b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ltr-ltr.html
new file mode 100644
index 000000000000..770ce7bd8a3b
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ltr-ltr.html
@@ -0,0 +1,73 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="htb-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  width: 400px;
+  margin: 16px 0;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container ltr">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ltr-rtl.tentative.html b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ltr-rtl.tentative.html
new file mode 100644
index 000000000000..abc8585ab24d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ltr-rtl.tentative.html
@@ -0,0 +1,73 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="htb-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  width: 400px;
+  margin: 16px 0;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container ltr">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ref.html b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ref.html
new file mode 100644
index 000000000000..bd534b077291
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-ref.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<style>
+.container {
+  background: green;
+  height: 16px;
+  border: solid black 3px;
+  width: 400px;
+  margin: 16px 0;
+}
+
+.large { height: 32px; }
+</style>
+
+There should be no red.
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
+
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
+
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/htb-rtl-ltr.tentative.html b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-rtl-ltr.tentative.html
new file mode 100644
index 000000000000..6a20341cbc63
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-rtl-ltr.tentative.html
@@ -0,0 +1,73 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="htb-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  width: 400px;
+  margin: 16px 0;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container rtl">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/htb-rtl-rtl.html b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-rtl-rtl.html
new file mode 100644
index 000000000000..279754ca4ea2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/htb-rtl-rtl.html
@@ -0,0 +1,73 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="htb-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  width: 400px;
+  margin: 16px 0;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container rtl">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ltr-ltr.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ltr-ltr.html
new file mode 100644
index 000000000000..1d95b46a0ff0
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ltr-ltr.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vlr-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-lr; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container ltr">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ltr-rtl.tentative.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ltr-rtl.tentative.html
new file mode 100644
index 000000000000..d3faab143044
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ltr-rtl.tentative.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vlr-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-lr; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container ltr">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ref.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ref.html
new file mode 100644
index 000000000000..2dc2012f0466
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-ref.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<style>
+body { writing-mode: vertical-lr; }
+.container {
+  background: green;
+  width: 16px;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+
+.large { width: 32px; }
+</style>
+
+There should be no red.
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
+
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
+
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-rtl-ltr.tentative.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-rtl-ltr.tentative.html
new file mode 100644
index 000000000000..736339ab54e5
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-rtl-ltr.tentative.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vlr-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-lr; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container rtl">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-rtl-rtl.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-rtl-rtl.html
new file mode 100644
index 000000000000..71f810fc7db3
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vlr-rtl-rtl.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vlr-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-lr; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container rtl">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ltr-ltr.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ltr-ltr.html
new file mode 100644
index 000000000000..d9e613a9eade
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ltr-ltr.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vrl-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-rl; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container ltr">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ltr-rtl.tentative.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ltr-rtl.tentative.html
new file mode 100644
index 000000000000..342d1cadfd14
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ltr-rtl.tentative.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vrl-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-rl; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container ltr">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr indent">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container ltr indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ref.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ref.html
new file mode 100644
index 000000000000..31be2b52cd98
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-ref.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<style>
+body { writing-mode: vertical-rl; }
+.container {
+  background: green;
+  width: 16px;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+
+.large { width: 32px; }
+</style>
+
+There should be no red.
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
+
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
+
+<div class="container"></div>
+
+<div class="container"></div>
+
+<div class="container large"></div>
+
+<div class="container large"></div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-rtl-ltr.tentative.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-rtl-ltr.tentative.html
new file mode 100644
index 000000000000..b0960490cfc2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-rtl-ltr.tentative.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vrl-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-rl; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container rtl">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="ltr cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="ltr">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-rtl-rtl.html b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-rtl-rtl.html
new file mode 100644
index 000000000000..8bdb06c8271e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-position/static-position/vrl-rtl-rtl.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width" />
+<link rel="match" href="vrl-ref.html">
+<meta name="assert" content="This test checks the static position of an out of flow absolute positioned element, under various conditions." />
+<style>
+body { writing-mode: vertical-rl; }
+.container {
+  position: relative;
+  background: green;
+  color: green;
+  font: 16px/1 Ahem;
+  border: solid black 3px;
+  height: 400px;
+  margin: 0 16px;
+}
+.red { color: red; }
+.cb { position: relative; }
+.rtl { direction: rtl; }
+.ltr { direction: ltr; }
+.inline { display: inline; }
+.abs { position: absolute; }
+
+.indent { text-indent: 20px; }
+* { text-indent: initial; }
+</style>
+
+There should be no red.
+<div class="container rtl">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl cb">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl indent">
+  XXX<span class="rtl cb">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs inline">XXXXX</div><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
+
+<div class="container rtl indent">
+  <span class="cb">XXX<span class="rtl">XX<div class="abs block">XXXXX</div><br><span class="red">XXXXX</span></span></span>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color-ref.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color-ref.html
index 44dd8d44d64c..a3dbad0b497d 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color-ref.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color-ref.html
@@ -23,7 +23,7 @@
     top: 100px;
 }
 .box2outside {
-    background: #000080;
+    background: #000088;
     position: absolute;
     width: 100px;
     height: 100px;
@@ -31,7 +31,7 @@
     top: 150px;
 }
 .box2inside {
-    background: #8040ff;
+    background: #773bff;
     position: absolute;
     width: 50px;
     height: 50px;
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color.html
index 39febb17d2df..c48cadeef67a 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-background-color.html
@@ -29,7 +29,6 @@
     left: 50px;
     top: 50px;
     backdrop-filter: invert(1);
-    opacity: 0.5;
-    background: blue;
+    background: #00f8;
 }
 </style>
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-opacity-2-ref.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-opacity-2-ref.html
new file mode 100644
index 000000000000..1027811f261a
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-opacity-2-ref.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>backdrop-filter: Basic operation of filter with opacity</title>
+<link rel="author" title="Mason Freed" href="mailto:masonfreed@chromium.org">
+
+
+
+<div>
+  <p>Expected: Just a single grey box.</p>
+</div>
+<div class="colorbox"></div>
+
+
+<style>
+.colorbox {
+    position: absolute;
+    background: #808080;
+    width: 100px;
+    height: 100px;
+    left: 10px;
+    top: 100px;
+}
+</style>
+
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-opacity-2.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-opacity-2.html
new file mode 100644
index 000000000000..8d7df67fbedb
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-basic-opacity-2.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>backdrop-filter: Basic operation of filter with opacity</title>
+<link rel="author" title="Mason Freed" href="mailto:masonfreed@chromium.org">
+<link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
+<link rel="match"  href="backdrop-filter-basic-opacity-2-ref.html">
+
+<div>
+  <p>Expected: Just a single grey box.</p>
+</div>
+<div class="box colorbox"></div>
+<div class="box filterbox"></div>
+
+<style>
+.box {
+    position: absolute;
+    width: 100px;
+    height: 100px;
+    left: 10px;
+    top: 100px;
+}
+.colorbox {
+    background: green;
+}
+.filterbox {
+    backdrop-filter: invert(1);
+    opacity: 0.5;
+    /* An invert backdrop-filter with opacity 0.5 should always give a grey
+       result. It will always mix the background color with its inverse, in
+       equal proportion.*/
+}
+</style>
+
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-clip-rect.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-clip-rect.html
index 8b5d9f4e34f8..075b34d513c2 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-clip-rect.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-clip-rect.html
@@ -3,7 +3,7 @@
 <title>backdrop-filter: Clip the filter at border box of element</title>
 <link rel="author" title="Mason Freed" href="mailto:masonfreed@chromium.org">
 <link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
-<link rel="match"  href="backdrop-filter-paint-order-ref.html">
+<link rel="match"  href="backdrop-filter-clip-rect-ref.html">
 
 <div>
   <p>Expected: A green box, blurred inside the short, wide white box with a<br>
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels-ref.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels-ref.html
index 1960435775c2..bbd562856f7a 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels-ref.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels-ref.html
@@ -6,7 +6,7 @@
 
 
 <div class="box"></div>
-<div style="position:absolute;top:100px;">
+<div style="position:absolute;top:100px;will-change:transform;">
   <p>Expected above: A pure white box with a blue border.<br>
   No dark/black should be observed within the white box.</p>
 </div>
@@ -20,6 +20,5 @@
   left: 0px;
   border: 1px solid blue;
 
-
 }
 </style>
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels.html
index 1e29d725ebcd..c26e70ce918c 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-edge-pixels.html
@@ -6,7 +6,7 @@
 <link rel="match"  href="backdrop-filter-edge-pixels-ref.html">
 
 <div class="box"></div>
-<div style="position:absolute;top:100px;">
+<div style="position:absolute;top:100px;will-change:transform;">
   <p>Expected above: A pure white box with a blue border.<br>
   No dark/black should be observed within the white box.</p>
 </div>
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-fixed.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-fixed.html
index c812d1f67436..a3c3fa25a850 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-fixed.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-fixed.html
@@ -5,28 +5,31 @@
 <link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
 <link rel="match"  href="backdrop-filter-isolation-ref.html">
 
-<div class="outside">
-  <div class="stacking-context">
-    <div class="filter">
+<div>
+  <p>Expected: Two green boxes overlapped by a yellow box. The overlapped region<br>
+  of the right-hand box ONLY should be inverted (pink).</p>
+</div>
+<div class="box outside">
+  <div class="box stacking-context">
+    <div class="box filter">
     </div>
   </div>
 </div>
 
-
 <style>
-div {
+.box {
   position: absolute;
   width: 100px;
   height: 100px;
   background: green;
 }
 .outside {
-  top: 10px;
+  top: 110px;
   left: 10px;
 }
 .stacking-context {
   position: fixed;
-  top: 10px;
+  top: 110px;
   left: 130px;
 }
 .filter {
@@ -34,9 +37,8 @@
   height: 160px;
   top: 30px;
   left: -90px;
-  opacity: 0.3;
   backdrop-filter: invert(1);
-  background: yellow;
+  background: #ff08;
 }
 </style>
 
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-isolate.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-isolate.html
index 99fa69d03fa6..88dd91ac8fe3 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-isolate.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-isolate.html
@@ -5,23 +5,26 @@
 <link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
 <link rel="match"  href="backdrop-filter-isolation-ref.html">
 
-<div class="outside">
-  <div class="stacking-context">
-    <div class="filter">
+<div>
+  <p>Expected: Two green boxes overlapped by a yellow box. The overlapped region<br>
+  of the right-hand box ONLY should be inverted (pink).</p>
+</div>
+<div class="box outside">
+  <div class="box stacking-context">
+    <div class="box filter">
     </div>
   </div>
 </div>
 
-
 <style>
-div {
+.box {
   position: absolute;
   width: 100px;
   height: 100px;
   background: green;
 }
 .outside {
-  top: 10px;
+  top: 110px;
   left: 10px;
 }
 .stacking-context {
@@ -34,9 +37,8 @@
   height: 160px;
   top: 30px;
   left: -90px;
-  opacity: 0.3;
   backdrop-filter: invert(1);
-  background: yellow;
+  background: #ff08;
 }
 </style>
 
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-ref.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-ref.html
index 58f5a7ec1edc..470704a688f3 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-ref.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation-ref.html
@@ -5,23 +5,26 @@
 
 
 
-<div class="outside">
-  <div class="stacking-context">
-    <div class="filter">
+<div>
+  <p>Expected: Two green boxes overlapped by a yellow box. The overlapped region<br>
+  of the right-hand box ONLY should be inverted (pink).</p>
+</div>
+<div class="box outside">
+  <div class="box stacking-context">
+    <div class="box filter">
     </div>
   </div>
 </div>
-<div style="background:#ffa5b2;width:70px;height:70px;top:40px;left:130px;"></div>
-
+<div class="box overlay"></div>
 <style>
-div {
+.box {
   position: absolute;
   width: 100px;
   height: 100px;
   background: green;
 }
 .outside {
-  top: 10px;
+  top: 110px;
   left: 10px;
 }
 .stacking-context {
@@ -34,9 +37,15 @@
   height: 160px;
   top: 30px;
   left: -90px;
-  opacity: 0.3;
   will-change: transform;
-  background: yellow;
+  background: #ff08;
+}
+.overlay {
+  background:#ffc377;
+  width:70px;
+  height:70px;
+  top:140px;
+  left:130px;
 }
 </style>
 
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation.html b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation.html
index e41772578e5d..500228df0816 100644
--- a/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation.html
+++ b/tests/wpt/web-platform-tests/css/filter-effects/backdrop-filter-isolation.html
@@ -5,23 +5,26 @@
 <link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
 <link rel="match"  href="backdrop-filter-isolation-ref.html">
 
-<div class="outside">
-  <div class="stacking-context">
-    <div class="filter">
+<div>
+  <p>Expected: Two green boxes overlapped by a yellow box. The overlapped region<br>
+  of the right-hand box ONLY should be inverted (pink).</p>
+</div>
+<div class="box outside">
+  <div class="box stacking-context">
+    <div class="box filter">
     </div>
   </div>
 </div>
 
-
 <style>
-div {
+.box {
   position: absolute;
   width: 100px;
   height: 100px;
   background: green;
 }
 .outside {
-  top: 10px;
+  top: 110px;
   left: 10px;
 }
 .stacking-context {
@@ -34,9 +37,8 @@
   height: 160px;
   top: 30px;
   left: -90px;
-  opacity: 0.3;
   backdrop-filter: invert(1);
-  background: yellow;
+  background: #ff08;
 }
 </style>
 
diff --git a/tests/wpt/web-platform-tests/interfaces/event-timing.idl b/tests/wpt/web-platform-tests/interfaces/event-timing.idl
index 0e12737bcc6e..cd727beead37 100644
--- a/tests/wpt/web-platform-tests/interfaces/event-timing.idl
+++ b/tests/wpt/web-platform-tests/interfaces/event-timing.idl
@@ -3,16 +3,19 @@
 // (https://github.com/tidoust/reffy-reports)
 // Source: Event Timing API (https://wicg.github.io/event-timing/)
 
+[Exposed=Window]
 interface PerformanceEventTiming : PerformanceEntry {
     readonly attribute DOMHighResTimeStamp processingStart;
     readonly attribute DOMHighResTimeStamp processingEnd;
     readonly attribute boolean cancelable;
 };
 
+[Exposed=Window]
 interface EventCounts {
     readonly maplike<DOMString, unsigned long>;
 };
 
+[Exposed=Window]
 partial interface Performance {
-    readonly attribute EventCounts eventCounts;
+    [SameObject] readonly attribute EventCounts eventCounts;
 };
diff --git a/tests/wpt/web-platform-tests/interfaces/web-nfc.idl b/tests/wpt/web-platform-tests/interfaces/web-nfc.idl
index d54773be4993..3dd4817eb0df 100644
--- a/tests/wpt/web-platform-tests/interfaces/web-nfc.idl
+++ b/tests/wpt/web-platform-tests/interfaces/web-nfc.idl
@@ -30,9 +30,13 @@ partial interface Navigator {
 
 typedef (DOMString or ArrayBuffer or NFCMessage) NFCMessageSource;
 
+[Constructor(), SecureContext, Exposed=Window]
+interface NFCWriter {
+  Promise<void> push(NFCMessageSource message, optional NFCPushOptions options);
+};
+
 [SecureContext]
 interface NFC {
-  Promise<void> push(NFCMessageSource message, optional NFCPushOptions options);
   Promise<void> watch(MessageCallback callback, optional NFCWatchOptions options);
 };
 
diff --git a/tests/wpt/web-platform-tests/media-source/mediasource-invalid-codec.html b/tests/wpt/web-platform-tests/media-source/mediasource-invalid-codec.html
new file mode 100644
index 000000000000..19aa00c4d5f4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/media-source/mediasource-invalid-codec.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>SourceBuffer handling of invalid codecs in the initialization segment</title>
+    <link rel="author" title="Alicia Boya García" href="mailto:aboya@igalia.com">
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <script src="mediasource-util.js"></script>
+</head>
+<body>
+<div id="log"></div>
+<script>
+    function testInvalidCodec(test, mediaElement, mediaSource, mediaType, url) {
+        assert_true(MediaSource.isTypeSupported(mediaType), `Media type not supported in this browser: isTypeSupported('${mediaType}')`);
+
+        MediaSourceUtil.loadBinaryData(test, url, (mediaData) => {
+            _testInvalidCodecWithData(test, mediaElement, mediaSource, mediaType, mediaData);
+        });
+    }
+
+    function _testInvalidCodecWithData(test, mediaElement, mediaSource, mediaType, mediaData) {
+        const sourceBuffer = mediaSource.addSourceBuffer(mediaType);
+        sourceBuffer.appendBuffer(mediaData);
+        test.expectEvent(sourceBuffer, 'error', 'Append ended with error');
+        test.waitForExpectedEvents(() => {
+            test.done();
+        })
+    }
+
+    // These test cases provide a typical media MIME type, but the actual files have been mangled to declare a different,
+    // unsupported, fictitious codec (MP4 fourcc: 'zzzz', WebM codec id 'V_ZZZ'). The browser should report a parsing
+    // error.
+
+    mediasource_test((test, mediaElement, mediaSource) => {
+        testInvalidCodec(test, mediaElement, mediaSource, 'video/mp4;codecs="avc1.4D4001"', 'mp4/invalid-codec.mp4');
+    }, 'Test an MP4 with an invalid codec results in an error.');
+
+    mediasource_test((test, mediaElement, mediaSource) => {
+        testInvalidCodec(test, mediaElement, mediaSource, 'video/webm; codecs="vp8"', 'webm/invalid-codec.webm');
+    }, 'Test a WebM with an invalid codec results in an error.');
+
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/media-source/mp4/invalid-codec.mp4 b/tests/wpt/web-platform-tests/media-source/mp4/invalid-codec.mp4
new file mode 100644
index 000000000000..6fcc7c21a698
Binary files /dev/null and b/tests/wpt/web-platform-tests/media-source/mp4/invalid-codec.mp4 differ
diff --git a/tests/wpt/web-platform-tests/media-source/webm/invalid-codec.webm b/tests/wpt/web-platform-tests/media-source/webm/invalid-codec.webm
new file mode 100644
index 000000000000..f1c8bdd7abba
Binary files /dev/null and b/tests/wpt/web-platform-tests/media-source/webm/invalid-codec.webm differ
diff --git a/tests/wpt/web-platform-tests/resources/chromium/mojo_layouttest_test.mojom.js b/tests/wpt/web-platform-tests/resources/chromium/mojo_web_test_helper_test.mojom.js
similarity index 54%
rename from tests/wpt/web-platform-tests/resources/chromium/mojo_layouttest_test.mojom.js
rename to tests/wpt/web-platform-tests/resources/chromium/mojo_web_test_helper_test.mojom.js
index babaeda156fc..cfbad0868987 100644
--- a/tests/wpt/web-platform-tests/resources/chromium/mojo_layouttest_test.mojom.js
+++ b/tests/wpt/web-platform-tests/resources/chromium/mojo_web_test_helper_test.mojom.js
@@ -5,7 +5,7 @@
 'use strict';
 
 (function() {
-  var mojomId = 'content/test/data/mojo_layouttest_test.mojom';
+  var mojomId = 'content/test/data/mojo_web_test_helper_test.mojom';
   if (mojo.internal.isMojomLoaded(mojomId)) {
     console.warn('The following mojom is loaded multiple times: ' + mojomId);
     return;
@@ -23,23 +23,23 @@
 
 
 
-  function MojoLayoutTestHelper_Reverse_Params(values) {
+  function MojoWebTestHelper_Reverse_Params(values) {
     this.initDefaults_();
     this.initFields_(values);
   }
 
 
-  MojoLayoutTestHelper_Reverse_Params.prototype.initDefaults_ = function() {
+  MojoWebTestHelper_Reverse_Params.prototype.initDefaults_ = function() {
     this.message = null;
   };
-  MojoLayoutTestHelper_Reverse_Params.prototype.initFields_ = function(fields) {
+  MojoWebTestHelper_Reverse_Params.prototype.initFields_ = function(fields) {
     for(var field in fields) {
         if (this.hasOwnProperty(field))
           this[field] = fields[field];
     }
   };
 
-  MojoLayoutTestHelper_Reverse_Params.validate = function(messageValidator, offset) {
+  MojoWebTestHelper_Reverse_Params.validate = function(messageValidator, offset) {
     var err;
     err = messageValidator.validateStructHeader(offset, codec.kStructHeaderSize);
     if (err !== validator.validationError.NONE)
@@ -53,7 +53,7 @@
         return err;
 
 
-    // validate MojoLayoutTestHelper_Reverse_Params.message
+    // validate MojoWebTestHelper_Reverse_Params.message
     err = messageValidator.validateStringPointer(offset + codec.kStructHeaderSize + 0, false)
     if (err !== validator.validationError.NONE)
         return err;
@@ -61,40 +61,40 @@
     return validator.validationError.NONE;
   };
 
-  MojoLayoutTestHelper_Reverse_Params.encodedSize = codec.kStructHeaderSize + 8;
+  MojoWebTestHelper_Reverse_Params.encodedSize = codec.kStructHeaderSize + 8;
 
-  MojoLayoutTestHelper_Reverse_Params.decode = function(decoder) {
+  MojoWebTestHelper_Reverse_Params.decode = function(decoder) {
     var packed;
-    var val = new MojoLayoutTestHelper_Reverse_Params();
+    var val = new MojoWebTestHelper_Reverse_Params();
     var numberOfBytes = decoder.readUint32();
     var version = decoder.readUint32();
     val.message = decoder.decodeStruct(codec.String);
     return val;
   };
 
-  MojoLayoutTestHelper_Reverse_Params.encode = function(encoder, val) {
+  MojoWebTestHelper_Reverse_Params.encode = function(encoder, val) {
     var packed;
-    encoder.writeUint32(MojoLayoutTestHelper_Reverse_Params.encodedSize);
+    encoder.writeUint32(MojoWebTestHelper_Reverse_Params.encodedSize);
     encoder.writeUint32(0);
     encoder.encodeStruct(codec.String, val.message);
   };
-  function MojoLayoutTestHelper_Reverse_ResponseParams(values) {
+  function MojoWebTestHelper_Reverse_ResponseParams(values) {
     this.initDefaults_();
     this.initFields_(values);
   }
 
 
-  MojoLayoutTestHelper_Reverse_ResponseParams.prototype.initDefaults_ = function() {
+  MojoWebTestHelper_Reverse_ResponseParams.prototype.initDefaults_ = function() {
     this.reversed = null;
   };
-  MojoLayoutTestHelper_Reverse_ResponseParams.prototype.initFields_ = function(fields) {
+  MojoWebTestHelper_Reverse_ResponseParams.prototype.initFields_ = function(fields) {
     for(var field in fields) {
         if (this.hasOwnProperty(field))
           this[field] = fields[field];
     }
   };
 
-  MojoLayoutTestHelper_Reverse_ResponseParams.validate = function(messageValidator, offset) {
+  MojoWebTestHelper_Reverse_ResponseParams.validate = function(messageValidator, offset) {
     var err;
     err = messageValidator.validateStructHeader(offset, codec.kStructHeaderSize);
     if (err !== validator.validationError.NONE)
@@ -108,7 +108,7 @@
         return err;
 
 
-    // validate MojoLayoutTestHelper_Reverse_ResponseParams.reversed
+    // validate MojoWebTestHelper_Reverse_ResponseParams.reversed
     err = messageValidator.validateStringPointer(offset + codec.kStructHeaderSize + 0, false)
     if (err !== validator.validationError.NONE)
         return err;
@@ -116,62 +116,62 @@
     return validator.validationError.NONE;
   };
 
-  MojoLayoutTestHelper_Reverse_ResponseParams.encodedSize = codec.kStructHeaderSize + 8;
+  MojoWebTestHelper_Reverse_ResponseParams.encodedSize = codec.kStructHeaderSize + 8;
 
-  MojoLayoutTestHelper_Reverse_ResponseParams.decode = function(decoder) {
+  MojoWebTestHelper_Reverse_ResponseParams.decode = function(decoder) {
     var packed;
-    var val = new MojoLayoutTestHelper_Reverse_ResponseParams();
+    var val = new MojoWebTestHelper_Reverse_ResponseParams();
     var numberOfBytes = decoder.readUint32();
     var version = decoder.readUint32();
     val.reversed = decoder.decodeStruct(codec.String);
     return val;
   };
 
-  MojoLayoutTestHelper_Reverse_ResponseParams.encode = function(encoder, val) {
+  MojoWebTestHelper_Reverse_ResponseParams.encode = function(encoder, val) {
     var packed;
-    encoder.writeUint32(MojoLayoutTestHelper_Reverse_ResponseParams.encodedSize);
+    encoder.writeUint32(MojoWebTestHelper_Reverse_ResponseParams.encodedSize);
     encoder.writeUint32(0);
     encoder.encodeStruct(codec.String, val.reversed);
   };
-  var kMojoLayoutTestHelper_Reverse_Name = 0;
+  var kMojoWebTestHelper_Reverse_Name = 0;
 
-  function MojoLayoutTestHelperPtr(handleOrPtrInfo) {
-    this.ptr = new bindings.InterfacePtrController(MojoLayoutTestHelper,
+  function MojoWebTestHelperPtr(handleOrPtrInfo) {
+    this.ptr = new bindings.InterfacePtrController(MojoWebTestHelper,
                                                    handleOrPtrInfo);
   }
 
-  function MojoLayoutTestHelperAssociatedPtr(associatedInterfacePtrInfo) {
+  function MojoWebTestHelperAssociatedPtr(associatedInterfacePtrInfo) {
     this.ptr = new associatedBindings.AssociatedInterfacePtrController(
-        MojoLayoutTestHelper, associatedInterfacePtrInfo);
+        MojoWebTestHelper, associatedInterfacePtrInfo);
   }
 
-  MojoLayoutTestHelperAssociatedPtr.prototype =
-      Object.create(MojoLayoutTestHelperPtr.prototype);
-  MojoLayoutTestHelperAssociatedPtr.prototype.constructor =
-      MojoLayoutTestHelperAssociatedPtr;
+  MojoWebTestHelperAssociatedPtr.prototype =
+      Object.create(MojoWebTestHelperPtr.prototype);
+  MojoWebTestHelperAssociatedPtr.prototype.constructor =
+      MojoWebTestHelperAssociatedPtr;
 
-  function MojoLayoutTestHelperProxy(receiver) {
+  function MojoWebTestHelperProxy(receiver) {
     this.receiver_ = receiver;
   }
-  MojoLayoutTestHelperPtr.prototype.reverse = function() {
-    return MojoLayoutTestHelperProxy.prototype.reverse
+  MojoWebTestHelperPtr.prototype.reverse = function() {
+    return MojoWebTestHelperProxy.prototype.reverse
         .apply(this.ptr.getProxy(), arguments);
   };
 
-  MojoLayoutTestHelperProxy.prototype.reverse = function(message) {
-    var params = new MojoLayoutTestHelper_Reverse_Params();
+  MojoWebTestHelperProxy.prototype.reverse = function(message) {
+    var params = new MojoWebTestHelper_Reverse_Params();
     params.message = message;
     return new Promise(function(resolve, reject) {
       var builder = new codec.MessageV1Builder(
-          kMojoLayoutTestHelper_Reverse_Name,
-          codec.align(MojoLayoutTestHelper_Reverse_Params.encodedSize),
+          kMojoWebTestHelper_Reverse_Name,
+          codec.align(MojoWebTestHelper_Reverse_Params.encodedSize),
           codec.kMessageExpectsResponse, 0);
-      builder.encodeStruct(MojoLayoutTestHelper_Reverse_Params, params);
+      builder.encodeStruct(MojoWebTestHelper_Reverse_Params, params);
       var message = builder.finish();
       this.receiver_.acceptAndExpectResponse(message).then(function(message) {
         var reader = new codec.MessageReader(message);
         var responseParams =
-            reader.decodeStruct(MojoLayoutTestHelper_Reverse_ResponseParams);
+            reader.decodeStruct(MojoWebTestHelper_Reverse_ResponseParams);
         resolve(responseParams);
       }).catch(function(result) {
         reject(Error("Connection error: " + result));
@@ -179,14 +179,14 @@
     }.bind(this));
   };
 
-  function MojoLayoutTestHelperStub(delegate) {
+  function MojoWebTestHelperStub(delegate) {
     this.delegate_ = delegate;
   }
-  MojoLayoutTestHelperStub.prototype.reverse = function(message) {
+  MojoWebTestHelperStub.prototype.reverse = function(message) {
     return this.delegate_ && this.delegate_.reverse && this.delegate_.reverse(message);
   }
 
-  MojoLayoutTestHelperStub.prototype.accept = function(message) {
+  MojoWebTestHelperStub.prototype.accept = function(message) {
     var reader = new codec.MessageReader(message);
     switch (reader.messageName) {
     default:
@@ -194,21 +194,21 @@
     }
   };
 
-  MojoLayoutTestHelperStub.prototype.acceptWithResponder =
+  MojoWebTestHelperStub.prototype.acceptWithResponder =
       function(message, responder) {
     var reader = new codec.MessageReader(message);
     switch (reader.messageName) {
-    case kMojoLayoutTestHelper_Reverse_Name:
-      var params = reader.decodeStruct(MojoLayoutTestHelper_Reverse_Params);
+    case kMojoWebTestHelper_Reverse_Name:
+      var params = reader.decodeStruct(MojoWebTestHelper_Reverse_Params);
       this.reverse(params.message).then(function(response) {
         var responseParams =
-            new MojoLayoutTestHelper_Reverse_ResponseParams();
+            new MojoWebTestHelper_Reverse_ResponseParams();
         responseParams.reversed = response.reversed;
         var builder = new codec.MessageV1Builder(
-            kMojoLayoutTestHelper_Reverse_Name,
-            codec.align(MojoLayoutTestHelper_Reverse_ResponseParams.encodedSize),
+            kMojoWebTestHelper_Reverse_Name,
+            codec.align(MojoWebTestHelper_Reverse_ResponseParams.encodedSize),
             codec.kMessageIsResponse, reader.requestID);
-        builder.encodeStruct(MojoLayoutTestHelper_Reverse_ResponseParams,
+        builder.encodeStruct(MojoWebTestHelper_Reverse_ResponseParams,
                              responseParams);
         var message = builder.finish();
         responder.accept(message);
@@ -219,13 +219,13 @@
     }
   };
 
-  function validateMojoLayoutTestHelperRequest(messageValidator) {
+  function validateMojoWebTestHelperRequest(messageValidator) {
     var message = messageValidator.message;
     var paramsClass = null;
     switch (message.getName()) {
-      case kMojoLayoutTestHelper_Reverse_Name:
+      case kMojoWebTestHelper_Reverse_Name:
         if (message.expectsResponse())
-          paramsClass = MojoLayoutTestHelper_Reverse_Params;
+          paramsClass = MojoWebTestHelper_Reverse_Params;
       break;
     }
     if (paramsClass === null)
@@ -233,13 +233,13 @@
     return paramsClass.validate(messageValidator, messageValidator.message.getHeaderNumBytes());
   }
 
-  function validateMojoLayoutTestHelperResponse(messageValidator) {
+  function validateMojoWebTestHelperResponse(messageValidator) {
    var message = messageValidator.message;
    var paramsClass = null;
    switch (message.getName()) {
-      case kMojoLayoutTestHelper_Reverse_Name:
+      case kMojoWebTestHelper_Reverse_Name:
         if (message.isResponse())
-          paramsClass = MojoLayoutTestHelper_Reverse_ResponseParams;
+          paramsClass = MojoWebTestHelper_Reverse_ResponseParams;
         break;
     }
     if (paramsClass === null)
@@ -247,18 +247,18 @@
     return paramsClass.validate(messageValidator, messageValidator.message.getHeaderNumBytes());
   }
 
-  var MojoLayoutTestHelper = {
-    name: 'content.mojom.MojoLayoutTestHelper',
+  var MojoWebTestHelper = {
+    name: 'content.mojom.MojoWebTestHelper',
     kVersion: 0,
-    ptrClass: MojoLayoutTestHelperPtr,
-    proxyClass: MojoLayoutTestHelperProxy,
-    stubClass: MojoLayoutTestHelperStub,
-    validateRequest: validateMojoLayoutTestHelperRequest,
-    validateResponse: validateMojoLayoutTestHelperResponse,
+    ptrClass: MojoWebTestHelperPtr,
+    proxyClass: MojoWebTestHelperProxy,
+    stubClass: MojoWebTestHelperStub,
+    validateRequest: validateMojoWebTestHelperRequest,
+    validateResponse: validateMojoWebTestHelperResponse,
   };
-  MojoLayoutTestHelperStub.prototype.validator = validateMojoLayoutTestHelperRequest;
-  MojoLayoutTestHelperProxy.prototype.validator = validateMojoLayoutTestHelperResponse;
-  exports.MojoLayoutTestHelper = MojoLayoutTestHelper;
-  exports.MojoLayoutTestHelperPtr = MojoLayoutTestHelperPtr;
-  exports.MojoLayoutTestHelperAssociatedPtr = MojoLayoutTestHelperAssociatedPtr;
+  MojoWebTestHelperStub.prototype.validator = validateMojoWebTestHelperRequest;
+  MojoWebTestHelperProxy.prototype.validator = validateMojoWebTestHelperResponse;
+  exports.MojoWebTestHelper = MojoWebTestHelper;
+  exports.MojoWebTestHelperPtr = MojoWebTestHelperPtr;
+  exports.MojoWebTestHelperAssociatedPtr = MojoWebTestHelperAssociatedPtr;
 })();
diff --git a/tests/wpt/web-platform-tests/resources/chromium/mojo_layouttest_test.mojom.js.headers b/tests/wpt/web-platform-tests/resources/chromium/mojo_web_test_helper_test.mojom.js.headers
similarity index 100%
rename from tests/wpt/web-platform-tests/resources/chromium/mojo_layouttest_test.mojom.js.headers
rename to tests/wpt/web-platform-tests/resources/chromium/mojo_web_test_helper_test.mojom.js.headers
diff --git a/tests/wpt/web-platform-tests/resources/test/tests/functional/api-tests-1.html b/tests/wpt/web-platform-tests/resources/test/tests/functional/api-tests-1.html
index 49f962a60c7b..1c108c5a638b 100644
--- a/tests/wpt/web-platform-tests/resources/test/tests/functional/api-tests-1.html
+++ b/tests/wpt/web-platform-tests/resources/test/tests/functional/api-tests-1.html
@@ -190,10 +190,7 @@ <h1>Sample HTML5 API Tests</h1>
 
     async_test("test should timeout (fail) with the default of 2 seconds").step(function(){});
 
-    async_test("test should timeout (fail) with a custom set timeout value of 1 second",
-               {timeout:1000}).step(function(){});
-
-    async_test("async test that is never started, should have status Not Run", {timeout:1000});
+    async_test("async test that is never started, should have status Not Run");
 
 
     test(function(t) {
@@ -344,9 +341,7 @@ <h1>Sample HTML5 API Tests</h1>
       "status_string": "NOTRUN",
       "name": "async test that is never started, should have status Not Run",
       "message": null,
-      "properties": {
-        "timeout": 1000
-      }
+      "properties": {}
     },
     {
       "status_string": "PASS",
@@ -402,14 +397,6 @@ <h1>Sample HTML5 API Tests</h1>
       "message": null,
       "properties": {}
     },
-    {
-      "status_string": "TIMEOUT",
-      "name": "test should timeout (fail) with a custom set timeout value of 1 second",
-      "message": "Test timed out",
-      "properties": {
-        "timeout": 1000
-      }
-    },
     {
       "status_string": "TIMEOUT",
       "name": "test should timeout (fail) with the default of 2 seconds",
diff --git a/tests/wpt/web-platform-tests/resources/testharness.js b/tests/wpt/web-platform-tests/resources/testharness.js
index 2e14c30730d2..b08074b96bd6 100644
--- a/tests/wpt/web-platform-tests/resources/testharness.js
+++ b/tests/wpt/web-platform-tests/resources/testharness.js
@@ -1486,11 +1486,9 @@ policies and contribution forms [3].
         this.index = null;
 
         this.properties = properties;
-        var timeout = properties.timeout ? properties.timeout : settings.test_timeout;
-        if (timeout !== null) {
-            this.timeout_length = timeout * tests.timeout_multiplier;
-        } else {
-            this.timeout_length = null;
+        this.timeout_length = settings.test_timeout;
+        if (this.timeout_length !== null) {
+            this.timeout_length *= tests.timeout_multiplier;
         }
 
         this.message = null;
diff --git a/tests/wpt/web-platform-tests/scroll-animations/current-time.html b/tests/wpt/web-platform-tests/scroll-animations/current-time.html
new file mode 100644
index 000000000000..8c70594612ac
--- /dev/null
+++ b/tests/wpt/web-platform-tests/scroll-animations/current-time.html
@@ -0,0 +1,306 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>ScrollTimeline current time algorithm</title>
+<link rel="help" href="https://wicg.github.io/scroll-animations/#current-time-algorithm">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script src="./resources/scrolltimeline-utils.js"></script>
+
+<body></body>
+
+<script>
+test(function() {
+  const scroller = setupScrollTimelineTest();
+  // Set the timeRange such that currentTime maps directly to the value
+  // scrolled. The contents and scroller are square, so it suffices to compute
+  // one edge and use it for all the timelines.
+  const scrollerSize = scroller.scrollHeight - scroller.clientHeight;
+
+  const blockScrollTimeline = new ScrollTimeline(
+      {scrollSource: scroller, timeRange: scrollerSize, orientation: 'block'});
+  const inlineScrollTimeline = new ScrollTimeline(
+      {scrollSource: scroller, timeRange: scrollerSize, orientation: 'inline'});
+  const horizontalScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'horizontal'
+  });
+  const verticalScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'vertical'
+  });
+
+  // Unscrolled, all timelines should read a currentTime of 0.
+  assert_equals(
+      blockScrollTimeline.currentTime, 0, 'Unscrolled block timeline');
+  assert_equals(
+      inlineScrollTimeline.currentTime, 0, 'Unscrolled inline timeline');
+  assert_equals(
+      horizontalScrollTimeline.currentTime, 0,
+      'Unscrolled horizontal timeline');
+  assert_equals(
+      verticalScrollTimeline.currentTime, 0, 'Unscrolled vertical timeline');
+
+  // Do some scrolling and make sure that the ScrollTimelines update.
+  scroller.scrollTop = 50;
+  scroller.scrollLeft = 75;
+
+  // As noted above timeRange is mapped such that currentTime should be the
+  // scroll offset.
+  assert_equals(blockScrollTimeline.currentTime, 50, 'Scrolled block timeline');
+  assert_equals(
+      inlineScrollTimeline.currentTime, 75, 'Scrolled inline timeline');
+  assert_equals(
+      horizontalScrollTimeline.currentTime, 75, 'Scrolled horizontal timeline');
+  assert_equals(
+      verticalScrollTimeline.currentTime, 50, 'Scrolled vertical timeline');
+}, 'currentTime calculates the correct time based on scrolled amount');
+
+test(function() {
+  // It is difficult to calculate the scroll offset which results in an exact
+  // currentTime. Scrolling is calculated in integers which allows for the
+  // possibility of rounding, and scrollbar widths differ between platforms
+  // which means it is not possible to ensure a divisible scroller size. Instead
+  // the scroller content is made large enough that rounding differences result
+  // in negligible deltas in the output value.
+  const contentOverrides = new Map([['width', '1000px'], ['height', '1000px']]);
+  const scroller = setupScrollTimelineTest(new Map(), contentOverrides);
+  const scrollTimeline = new ScrollTimeline(
+      {scrollSource: scroller, timeRange: 100, orientation: 'block'});
+
+  // Mapping timeRange to 100 means the output is 'percentage scrolled', so
+  // calculate where the 50% scroll mark would be.
+  const halfwayY = (scroller.scrollHeight - scroller.clientHeight) / 2;
+  scroller.scrollTop = halfwayY;
+
+  assert_approx_equals(scrollTimeline.currentTime, 50, 0.5);
+}, 'currentTime adjusts correctly for the timeRange');
+
+test(function() {
+  const scroller = setupScrollTimelineTest();
+  // Set the timeRange such that currentTime maps directly to the value
+  // scrolled. The contents and scroller are square, so it suffices to compute
+  // one edge and use it for all the timelines.
+  const scrollerSize = scroller.scrollHeight - scroller.clientHeight;
+
+  const lengthScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    startScrollOffset: '20px'
+  });
+  const percentageScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    startScrollOffset: '20%'
+  });
+  const calcScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    startScrollOffset: 'calc(20% - 5px)'
+  });
+
+  // Unscrolled all timelines should read a current time of unresolved, as the
+  // current offset (0) will be less than the startScrollOffset.
+  assert_equals(
+      lengthScrollTimeline.currentTime, null,
+      'Unscrolled length-based timeline');
+  assert_equals(
+      percentageScrollTimeline.currentTime, null,
+      'Unscrolled percentage-based timeline');
+  assert_equals(
+      calcScrollTimeline.currentTime, null, 'Unscrolled calc-based timeline');
+
+  // Check the length-based ScrollTimeline.
+  scroller.scrollTop = 19;
+  assert_equals(
+      lengthScrollTimeline.currentTime, null,
+      'Length-based timeline before the startScrollOffset point');
+  scroller.scrollTop = 20;
+  assert_equals(
+      lengthScrollTimeline.currentTime, 0,
+      'Length-based timeline at the startScrollOffset point');
+  scroller.scrollTop = 50;
+  assert_equals(
+      lengthScrollTimeline.currentTime,
+      calculateCurrentTime(50, 20, scrollerSize, scrollerSize),
+      'Length-based timeline after the startScrollOffsetPoint');
+
+  // Check the percentage-based ScrollTimeline.
+  scroller.scrollTop = 0.19 * scrollerSize;
+  assert_equals(
+      percentageScrollTimeline.currentTime, null,
+      'Percentage-based scroller before the startScrollOffset point');
+  scroller.scrollTop = 0.20 * scrollerSize;
+  assert_equals(
+      percentageScrollTimeline.currentTime, 0,
+      'Percentage-based scroller at the startScrollOffset point');
+  scroller.scrollTop = 0.50 * scrollerSize;
+  assert_equals(
+      percentageScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scroller.scrollTop, 0.2 * scrollerSize, scrollerSize, scrollerSize),
+      'Percentage-based scroller after the startScrollOffset point');
+
+  // Check the calc-based ScrollTimeline.
+  scroller.scrollTop = 0.2 * scrollerSize - 10;
+  assert_equals(
+      calcScrollTimeline.currentTime, null,
+      'Calc-based scroller before the startScrollOffset point');
+  scroller.scrollTop = 0.2 * scrollerSize - 5;
+  assert_equals(
+      calcScrollTimeline.currentTime, 0,
+      'Calc-based scroller at the startScrollOffset point');
+  scroller.scrollTop = 0.2 * scrollerSize;
+  assert_equals(
+      calcScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scroller.scrollTop, 0.2 * scrollerSize - 5, scrollerSize,
+          scrollerSize),
+      'Calc-based scroller after the startScrollOffset point');
+}, 'currentTime handles startScrollOffset correctly');
+
+test(function() {
+  const scroller = setupScrollTimelineTest();
+  // Set the timeRange such that currentTime maps directly to the value
+  // scrolled. The contents and scroller are square, so it suffices to compute
+  // one edge and use it for all the timelines.
+  const scrollerSize = scroller.scrollHeight - scroller.clientHeight;
+
+  const lengthScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    endScrollOffset: (scrollerSize - 20) + 'px'
+  });
+  const percentageScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    endScrollOffset: '80%'
+  });
+  const calcScrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    endScrollOffset: 'calc(80% + 5px)'
+  });
+
+  // Check the length-based ScrollTimeline.
+  scroller.scrollTop = scrollerSize;
+  assert_equals(
+      lengthScrollTimeline.currentTime, null,
+      'Length-based timeline after the endScrollOffset point');
+  scroller.scrollTop = scrollerSize - 20;
+  assert_equals(
+      lengthScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scrollerSize - 20, 0, scrollerSize - 20, scrollerSize),
+      'Length-based timeline at the endScrollOffset point');
+  scroller.scrollTop = scrollerSize - 50;
+  assert_equals(
+      lengthScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scrollerSize - 50, 0, scrollerSize - 20, scrollerSize),
+      'Length-based timeline before the endScrollOffset point');
+
+  // Check the percentage-based ScrollTimeline.
+  scroller.scrollTop = 0.81 * scrollerSize;
+  assert_equals(
+      percentageScrollTimeline.currentTime, null,
+      'Percentage-based timeline after the endScrollOffset point');
+  scroller.scrollTop = 0.80 * scrollerSize;
+  assert_equals(
+      percentageScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scroller.scrollTop, 0, 0.8 * scrollerSize, scrollerSize),
+      'Percentage-based timeline at the endScrollOffset point');
+  scroller.scrollTop = 0.50 * scrollerSize;
+  assert_equals(
+      percentageScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scroller.scrollTop, 0, 0.8 * scrollerSize, scrollerSize),
+      'Percentage-based timeline before the endScrollOffset point');
+
+  // Check the calc-based ScrollTimeline.
+  scroller.scrollTop = 0.8 * scrollerSize + 6;
+  assert_equals(
+      calcScrollTimeline.currentTime, null,
+      'Calc-based timeline after the endScrollOffset point');
+  scroller.scrollTop = 0.8 * scrollerSize + 5;
+  assert_equals(
+      calcScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scroller.scrollTop, 0, 0.8 * scrollerSize + 5, scrollerSize),
+      'Calc-based timeline at the endScrollOffset point');
+  scroller.scrollTop = 0.5 * scrollerSize;
+  assert_equals(
+      calcScrollTimeline.currentTime,
+      calculateCurrentTime(
+          scroller.scrollTop, 0, 0.8 * scrollerSize + 5, scrollerSize),
+      'Calc-based timeline before the endScrollOffset point');
+}, 'currentTime handles endScrollOffset correctly');
+
+test(function() {
+  const scroller = setupScrollTimelineTest();
+  // Set the timeRange such that currentTime maps directly to the value
+  // scrolled. The contents and scroller are square, so it suffices to compute
+  // one edge and use it for all the timelines.
+  const scrollerSize = scroller.scrollHeight - scroller.clientHeight;
+
+  const scrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    startScrollOffset: '20px',
+    endScrollOffset: (scrollerSize - 50) + 'px'
+  });
+
+  scroller.scrollTop = 150;
+  assert_equals(
+      scrollTimeline.currentTime,
+      calculateCurrentTime(150, 20, scrollerSize - 50, scrollerSize));
+}, 'currentTime handles startScrollOffset and endScrollOffset together correctly');
+
+test(function() {
+  const scroller = setupScrollTimelineTest();
+  // Set the timeRange such that currentTime maps directly to the value
+  // scrolled. The contents and scroller are square, so it suffices to compute
+  // one edge and use it for all the timelines.
+  const scrollerSize = scroller.scrollHeight - scroller.clientHeight;
+
+  const scrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    startScrollOffset: '20px',
+    endScrollOffset: '20px',
+  });
+
+  scroller.scrollTop = 150;
+  assert_equals(scrollTimeline.currentTime, null);
+}, 'currentTime handles startScrollOffset == endScrollOffset correctly');
+
+test(function() {
+  const scroller = setupScrollTimelineTest();
+  // Set the timeRange such that currentTime maps directly to the value
+  // scrolled. The contents and scroller are square, so it suffices to compute
+  // one edge and use it for all the timelines.
+  const scrollerSize = scroller.scrollHeight - scroller.clientHeight;
+
+  const scrollTimeline = new ScrollTimeline({
+    scrollSource: scroller,
+    timeRange: scrollerSize,
+    orientation: 'block',
+    startScrollOffset: '50px',
+    endScrollOffset: '10px',
+  });
+
+  scroller.scrollTop = 150;
+  assert_equals(scrollTimeline.currentTime, null);
+}, 'currentTime handles startScrollOffset > endScrollOffset correctly');
+</script>
diff --git a/tests/wpt/web-platform-tests/scroll-animations/resources/scrolltimeline-utils.js b/tests/wpt/web-platform-tests/scroll-animations/resources/scrolltimeline-utils.js
new file mode 100644
index 000000000000..b0e5ead25c6e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/scroll-animations/resources/scrolltimeline-utils.js
@@ -0,0 +1,44 @@
+'use strict';
+
+// Builds a generic structure that looks like:
+//
+// <div class="scroller">  // 100x100 viewport
+//   <div class="contents"></div>  // 500x500
+// </div>
+//
+// The |scrollerOverrides| and |contentOverrides| parameters are maps which
+// are applied to the scroller and contents style after basic setup.
+//
+// Appends the outer 'scroller' element to the document body, and returns it.
+function setupScrollTimelineTest(
+    scrollerOverrides = new Map(), contentOverrides = new Map()) {
+  let scroller = document.createElement('div');
+  scroller.style.width = '100px';
+  scroller.style.height = '100px';
+  scroller.style.overflow = 'scroll';
+  for (const [key, value] of scrollerOverrides) {
+    scroller.style[key] = value;
+  }
+
+  let contents = document.createElement('div');
+  contents.style.width = '500px';
+  contents.style.height = '500px';
+  for (const [key, value] of contentOverrides) {
+    contents.style[key] = value;
+  }
+
+  scroller.appendChild(contents);
+  document.body.appendChild(scroller);
+  return scroller;
+}
+
+// Helper method to calculate the current time, implementing only step 5 of
+// https://wicg.github.io/scroll-animations/#current-time-algorithm
+function calculateCurrentTime(
+    currentScrollOffset, startScrollOffset, endScrollOffset,
+    effectiveTimeRange) {
+  return ((currentScrollOffset - startScrollOffset) /
+          (endScrollOffset - startScrollOffset)) *
+      effectiveTimeRange;
+}
+
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/fetch-request-css-base-url.https.html b/tests/wpt/web-platform-tests/service-workers/service-worker/fetch-request-css-base-url.https.html
index 7feccfb98c56..a08e0c748813 100644
--- a/tests/wpt/web-platform-tests/service-workers/service-worker/fetch-request-css-base-url.https.html
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/fetch-request-css-base-url.https.html
@@ -1,58 +1,87 @@
 <!DOCTYPE html>
-<title>Service Worker: CSS's base URL must be the request URL even when fetched from other URL</title>
+<title>Service Worker: CSS's base URL must be the response URL</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<script src="/common/get-host-info.sub.js"></script>
 <script src="resources/test-helpers.sub.js?pipe=sub"></script>
 <script>
-promise_test(function(t) {
-    var SCOPE = 'resources/fetch-request-css-base-url-iframe.html';
-    var SCRIPT = 'resources/fetch-request-css-base-url-worker.js';
-    var worker;
-    var testDonePromise;
-
-    return service_worker_unregister_and_register(t, SCRIPT, SCOPE)
-      .then(function(registration) {
-          t.add_cleanup(function() {
-              return service_worker_unregister(t, SCOPE);
-            });
-
-          worker = registration.installing;
-          return wait_for_state(t, worker, 'activated');
-        })
-      .then(function() {
-          return new Promise(function(resolve) {
-              var channel = new MessageChannel();
-              testDonePromise = new Promise(function(resolveTestDone) {
-                channel.port1.onmessage = t.step_func(function(msg) {
-                  if (msg.data.ready) {
-                    resolve();
-                    return;
-                  }
-                  var result = msg.data;
-                  var base = get_host_info()['HTTPS_ORIGIN'] + base_path();
-                  assert_equals(
-                    result.url,
-                    base + 'resources/dummy.png',
-                    'The base URL while loading the images referred from CSS ' +
-                    'must be the request URL of CSS.');
-                  assert_equals(
-                    result.referrer,
-                    base + 'resources/fetch-request-css-base-url-style.css',
-                    'While loading the image defined in CSS the referrer must ' +
-                    'be the request URL of CSS.');
-                  resolveTestDone();
-                });
-              });
-              worker.postMessage(
-                {port: channel.port2}, [channel.port2]);
-            });
-        })
-      .then(function() { return with_iframe(SCOPE); })
-      .then(function(f) {
-          return testDonePromise.then(function() {
-            f.remove();
-          });
-        });
-  }, 'CSS\'s base URL must be the request URL even when fetched from other URL.');
+const SCOPE = 'resources/fetch-request-css-base-url-iframe.html';
+const SCRIPT = 'resources/fetch-request-css-base-url-worker.js';
+let worker;
+
+var signalMessage;
+function getNextMessage() {
+  return new Promise(resolve => { signalMessage = resolve; });
+}
+
+promise_test(async (t) => {
+  const registration = await service_worker_unregister_and_register(
+      t, SCRIPT, SCOPE);
+  worker = registration.installing;
+  await wait_for_state(t, worker, 'activated');
+}, 'global setup');
+
+// Creates a test concerning the base URL of a stylesheet. It loads a
+// stylesheet from a controlled page. The stylesheet makes a subresource
+// request for an image. The service worker messages back the details of the
+// image request in order to test the base URL.
+//
+// The request URL for the stylesheet is under "resources/request-url-path/".
+// The service worker may respond in a way such that the response URL is
+// different to the request URL.
+function base_url_test(params) {
+  promise_test(async (t) => {
+    let frame;
+    t.add_cleanup(() => {
+      if (frame)
+        frame.remove();
+    });
+
+    // Ask the service worker to message this page once it gets the request
+    // for the image.
+    let channel = new MessageChannel();
+    const sawPong = getNextMessage();
+    channel.port1.onmessage = (event) => {
+      signalMessage(event.data);
+    };
+    worker.postMessage({port:channel.port2},[channel.port2]);
+
+    // It sends a pong back immediately. This ping/pong protocol helps deflake
+    // the test for browsers where message/fetch ordering isn't guaranteed.
+    assert_equals('pong', await sawPong);
+
+    // Load the frame which will load the stylesheet that makes the image
+    // request.
+    const sawResult = getNextMessage();
+    frame = await with_iframe(params.framePath);
+    const result = await sawResult;
+
+    // Test the image request.
+    const base = new URL('.', document.location).href;
+    assert_equals(result.url,
+                  base + params.expectImageRequestPath,
+                  'request');
+    assert_equals(result.referrer,
+                  base + params.expectImageRequestReferrer,
+                  'referrer');
+  }, params.description);
+}
+
+const cssFile = 'fetch-request-css-base-url-style.css';
+
+base_url_test({
+  framePath: SCOPE + '?fetch',
+  expectImageRequestPath: 'resources/dummy.png',
+  expectImageRequestReferrer: `resources/${cssFile}?fetch`,
+  description: 'base URL when service worker does respondWith(fetch(responseUrl)).'});
+
+base_url_test({
+  framePath: SCOPE + '?newResponse',
+  expectImageRequestPath: 'resources/request-url-path/dummy.png',
+  expectImageRequestReferrer: `resources/request-url-path/${cssFile}?newResponse`,
+  description: 'base URL when service worker does respondWith(new Response()).'});
+
+// Cleanup step: this must be the last promise_test.
+promise_test(async (t) => {
+  return service_worker_unregister(t, SCOPE);
+}, 'cleanup global state');
 </script>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-iframe.html b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-iframe.html
index 0edf2e7f9659..504e10435642 100644
--- a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-iframe.html
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-iframe.html
@@ -1 +1,20 @@
-<link href="./fetch-request-css-base-url-style.css" rel="stylesheet" type="text/css">
+<html>
+<head>
+<title>iframe for css base url test</title>
+</head>
+<body>
+<script>
+// Load a stylesheet. Create it dynamically so we can construct the href URL
+// dynamically.
+const link = document.createElement('link');
+link.rel = 'stylesheet';
+link.type = 'text/css';
+// Add "request-url-path" to the path to help distinguish the request URL from
+// the response URL. Add |document.location.search| (chosen by the test main
+// page) to tell the service worker how to respond to the request.
+link.href = 'request-url-path/fetch-request-css-base-url-style.css' +
+    document.location.search;
+document.head.appendChild(link);
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-worker.js b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-worker.js
index 91c325998a3b..e8dbd2725c68 100644
--- a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-worker.js
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-css-base-url-worker.js
@@ -1,27 +1,45 @@
-importScripts('/common/get-host-info.sub.js');
-importScripts('test-helpers.sub.js');
+let source;
+let resolveDone;
+let done = new Promise(resolve => resolveDone = resolve);
 
-var port = undefined;
+// The page messages this worker to ask for the result. Keep the worker alive
+// via waitUntil() until the result is sent.
+self.addEventListener('message', event => {
+  source = event.data.port;
+  source.postMessage('pong');
+  event.waitUntil(done);
+});
 
-self.onmessage = function(e) {
-  var message = e.data;
-  if ('port' in message) {
-    port = message.port;
-    port.postMessage({ready: true});
-  }
-};
+self.addEventListener('fetch', event => {
+  const url = new URL(event.request.url);
 
-self.addEventListener('fetch', function(event) {
-    var url = event.request.url;
-    if (url.indexOf('fetch-request-css-base-url-style.css') != -1) {
-      event.respondWith(fetch(
-        get_host_info()['HTTPS_REMOTE_ORIGIN'] + base_path() +
-        'fetch-request-css-base-url-style.css',
-        {mode: 'no-cors'}));
-    } else if (url.indexOf('dummy.png') != -1) {
-      port.postMessage({
-          url: event.request.url,
-          referrer: event.request.referrer
-        });
+  // For the CSS file, respond in a way that may change the response URL,
+  // depending on |url.search|.
+  const cssPath = 'request-url-path/fetch-request-css-base-url-style.css';
+  if (url.pathname.indexOf(cssPath) != -1) {
+    // Respond with a different URL, deleting "request-url-path/".
+    if (url.search == '?fetch') {
+      event.respondWith(fetch('fetch-request-css-base-url-style.css'));
+    }
+    // Respond with new Response().
+    else if (url.search == '?newResponse') {
+      const styleString = 'body { background-image: url("./dummy.png");}';
+      const headers = {'content-type': 'text/css'};
+      event.respondWith(new Response(styleString, headers));
     }
-  });
+  }
+
+  // The image request indicates what the base URL of the CSS was. Message the
+  // result back to the test page.
+  else if (url.pathname.indexOf('dummy.png') != -1) {
+    // For some reason |source| is undefined here when running the test manually
+    // in Firefox. The test author experimented with both using Client
+    // (event.source) and MessagePort to try to get the test to pass, but
+    // failed.
+    source.postMessage({
+      url: event.request.url,
+      referrer: event.request.referrer
+    });
+    resolveDone();
+  }
+});
diff --git a/tests/wpt/web-platform-tests/svg/interact/scripted/composed.window.svg b/tests/wpt/web-platform-tests/svg/interact/scripted/composed.window.svg
new file mode 100644
index 000000000000..b63dcf024439
--- /dev/null
+++ b/tests/wpt/web-platform-tests/svg/interact/scripted/composed.window.svg
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml">
+    <title>Focus events are composed</title>
+    <metadata>
+        <h:link rel="help" href="https://svgwg.org/svg2-draft/interact.html#Focus"/>
+    </metadata>
+    <a id="a1" href="#"></a>
+    <h:script src="/resources/testharness.js"/>
+    <h:script src="/resources/testharnessreport.js"/>
+    <script><![CDATA[
+    async_test(t => {
+        const anchor = document.getElementById("a1");
+        let happened = false;
+        anchor.onfocus = t.step_func(e => {
+            happened = true;
+            assert_equals(e.type, "focus");
+            assert_true(e.composed);
+        });
+        anchor.focus();
+        anchor.onblur = t.step_func_done(e => {
+            assert_true(happened);
+            assert_equals(e.type, "blur");
+            assert_true(e.composed);
+        });
+        anchor.blur();
+    }, "Focus events are composed");
+    ]]></script>
+</svg>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/svg/interact/scripted/focus-events.svg b/tests/wpt/web-platform-tests/svg/interact/scripted/focus-events.svg
new file mode 100644
index 000000000000..bf307b79fdf1
--- /dev/null
+++ b/tests/wpt/web-platform-tests/svg/interact/scripted/focus-events.svg
@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml">
+    <title>Focus management</title>
+    <metadata>
+        <h:link rel="help" href="https://svgwg.org/svg2-draft/interact.html#Focus"/>
+    </metadata>
+    <a id="a1" href="#"></a>
+    <a id="a2" href="#"></a>
+    <h:script src="/resources/testharness.js"/>
+    <h:script src="/resources/testharnessreport.js"/>
+    <script><![CDATA[
+    var a1 = document.getElementById('a1'),
+    a2 = document.getElementById('a2'),
+    t1 = async_test("focusing on a focusable element fires a focus event at the element"),
+    t2 = async_test("focusing on a focusable element fires a blur event at the previous focussed element");
+
+    a2.onfocus = t1.step_func_done(function(e){
+        assert_true(e.isTrusted, "focus event is trusted");
+        assert_false(e.bubbles, "focus event doesn't bubble");
+        assert_false(e.cancelable, "focus event is not cancelable");
+        assert_equals(document.activeElement, a2);
+    });
+
+    a1.onblur = t2.step_func_done(function(e){
+        assert_true(e.isTrusted, "blur event is trusted");
+        assert_false(e.bubbles, "blur event doesn't bubble");
+        assert_false(e.cancelable, "blur event is not cancelable");
+    });
+
+    a1.focus();
+    a2.focus();
+    ]]></script>
+</svg>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/svg/interact/scripted/focus-tabindex-default-value.svg b/tests/wpt/web-platform-tests/svg/interact/scripted/focus-tabindex-default-value.svg
new file mode 100644
index 000000000000..3af1acffd8de
--- /dev/null
+++ b/tests/wpt/web-platform-tests/svg/interact/scripted/focus-tabindex-default-value.svg
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml">
+    <title>SVG Test: focus - default value of tabindex</title>
+    <metadata>
+        <h:link rel="help" href="https://svgwg.org/svg2-draft/interact.html#Focus"/>
+    </metadata>
+    <a id="test1" href="#"></a>
+    <rect id="test2"></rect>
+    <h:script src="/resources/testharness.js"/>
+    <h:script src="/resources/testharnessreport.js"/>
+    <script><![CDATA[
+    test(function() {
+        assert_equals(document.getElementById("test1").tabIndex, 0, "The value of tabIndex attribute should be 0.");
+    }, "The default value of tabIndex attribute must be 0 for elements that are focusable");
+
+    test(function() {
+        assert_equals(document.getElementById("test2").tabIndex, -1, "The value of tabIndex attribute should be -1.");
+    }, "The default value of tabIndex attribute must be -1 for elements that are not focusable");
+    ]]></script>
+</svg>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/svg/interact/scripted/resources/blank.htm b/tests/wpt/web-platform-tests/svg/interact/scripted/resources/blank.htm
new file mode 100644
index 000000000000..18ecdcb795c3
--- /dev/null
+++ b/tests/wpt/web-platform-tests/svg/interact/scripted/resources/blank.htm
@@ -0,0 +1 @@
+<html></html>
diff --git a/tests/wpt/web-platform-tests/svg/interact/scripted/tabindex-focus-flag.svg b/tests/wpt/web-platform-tests/svg/interact/scripted/tabindex-focus-flag.svg
new file mode 100644
index 000000000000..29ba209b2bad
--- /dev/null
+++ b/tests/wpt/web-platform-tests/svg/interact/scripted/tabindex-focus-flag.svg
@@ -0,0 +1,125 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:h="http://www.w3.org/1999/xhtml">
+    <metadata>
+        <h:link rel="help" href="https://svgwg.org/svg2-draft/interact.html#Focus"/>
+    </metadata>
+    <g id="default-samples">
+        <!-- non-default focusable renderable element -->
+        <rect></rect>
+        <svg></svg>
+        <!-- for compatibility with SVG Tiny 1.2 focusable attribute, user agents should treat an element with a value of true for that attribute as focusable -->
+        <rect focusable="true"></rect>
+        <!-- anchors need a href to be focusable -->
+        <a></a>
+        <a href=""></a>
+        <!-- Remove default focus behaviour with focusable="false" (SVG Tiny 1.2 compatibility) -->
+        <a href="" focusable="false"></a>
+        <!-- iframe, and audio/video with controls are default focusable -->
+        <h:iframe src="resources/blank.htm"></h:iframe>
+        <h:audio controls="controls"></h:audio>
+        <h:video controls="controls"></h:video>
+        <!-- non-default focusable renderable element with valid tabindex -->
+        <h:canvas tabindex="0"></h:canvas>
+        <circle tabindex="0"></circle>
+        <ellipse tabindex="0"></ellipse>
+        <foreignObject tabindex="0"></foreignObject>
+        <g tabindex="0"></g>
+        <image tabindex="0"></image>
+        <line tabindex="0"></line>
+        <mesh tabindex="0"></mesh>
+        <path tabindex="0"></path>
+        <polygon tabindex="0"></polygon>
+        <rect tabindex="0"></rect>
+        <svg tabindex="0"></svg>
+        <switch tabindex="0"></switch>
+        <text tabindex="0">
+            <textPath tabindex="0"></textPath>
+            <tspan tabindex="0"></tspan>
+        </text>
+        <unknown tabindex="0"></unknown>
+        <use tabindex="0"></use>
+        <!-- never-rendered element with valid tabindex -->
+        <clipPath tabindex="0"></clipPath>
+        <defs tabindex="0"></defs>
+        <desc tabindex="0"></desc>
+        <hatch tabindex="0"></hatch>
+        <linearGradient tabindex="0"></linearGradient>
+        <marker tabindex="0"></marker>
+        <mask tabindex="0"></mask>
+        <meshgradient tabindex="0"></meshgradient>
+        <metadata tabindex="0"></metadata>
+        <pattern tabindex="0"></pattern>
+        <radialGradient tabindex="0"></radialGradient>
+        <script tabindex="0"></script>
+        <style tabindex="0"></style>
+        <title tabindex="0"></title>
+        <symbol tabindex="0"></symbol>
+    </g>
+    <h:script src="/resources/testharness.js"/>
+    <h:script src="/resources/testharnessreport.js"/>
+    <script><![CDATA[
+    var root = document.querySelector("svg");
+
+    test(() => {
+        root.focus();
+        assert_equals(document.activeElement, root);
+    }, 'The document root element should be focusable.');
+
+    const defaultList = [
+        ['rect', false],
+        ['svg', false],
+        ['rect[focusable=true]', true],
+        ['a', false],
+        ['a[href]', true],
+        ['a[focusable=false]', false],
+        ['iframe', true],
+        ['audio[controls]', true],
+        ['video[controls]', true],
+        ['canvas[tabindex]', true],
+        ['circle[tabindex]', true],
+        ['ellipse[tabindex]', true],
+        ['foreignObject[tabindex]', true],
+        ['g[tabindex]', true],
+        ['image[tabindex]', true],
+        ['line[tabindex]', true],
+        ['mesh[tabindex]', true],
+        ['path[tabindex]', true],
+        ['polygon[tabindex]', true],
+        ['rect[tabindex]', true],
+        ['svg[tabindex]', true],
+        ['switch[tabindex]', true],
+        ['text[tabindex]', true],
+        ['textPath[tabindex]', true],
+        ['tspan[tabindex]', true],
+        ['unknown[tabindex]', true],
+        ['use[tabindex]', true],
+        ['clipPath[tabindex]', false],
+        ['defs[tabindex]', false],
+        ['desc[tabindex]', false],
+        ['hatch[tabindex]', false],
+        ['linearGradient[tabindex]', false],
+        ['marker[tabindex]', false],
+        ['mask[tabindex]', false],
+        ['meshgradient[tabindex]', false],
+        ['metadata[tabindex]', false],
+        ['pattern[tabindex]', false],
+        ['radialGradient[tabindex]', false],
+        ['script[tabindex]', false],
+        ['style[tabindex]', false],
+        ['title[tabindex]', false],
+        ['symbol[tabindex]', false],
+    ];
+
+    for (entry of defaultList) {
+        test(() => {
+            var element = document.querySelector('#default-samples ' + entry[0]);
+            element.focus();
+            if (entry[1])
+            assert_equals(document.activeElement, element);
+            else
+            assert_not_equals(document.activeElement, element);
+        }, entry[0] + ' should ' + (entry[1] ? '' : 'not ') + 'be focusable.');
+    }
+    ]]></script>
+</svg>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-track-stats.https.html b/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-track-stats.https.html
index 9ad679272b57..30c368f670d7 100644
--- a/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-track-stats.https.html
+++ b/tests/wpt/web-platform-tests/webrtc/RTCPeerConnection-track-stats.https.html
@@ -155,11 +155,6 @@
     }));
   }, 'addTrack(): Media stream stats references track stats');
 
-  // TODO(hbos): addStream() is legacy API not in the spec. Based on discussion
-  // whether to standardize in legacy section, consider removing this test or
-  // keeping it until addTrack() has wide support.
-  // https://github.com/w3c/webrtc-pc/issues/1705
-  // https://github.com/w3c/webrtc-pc/issues/1125
   async_test(t => {
     const pc = new RTCPeerConnection();
     t.add_cleanup(() => pc.close());
@@ -170,7 +165,8 @@
       track = tracks[0];
       stream = streams[0];
       stream.addTrack(track);
-      pc.addStream(stream);
+      for (const track of stream.getTracks())
+        pc.addTrack(track, stream);
       return pc.createOffer();
     }))
     .then(t.step_func(offer => {
@@ -193,7 +189,7 @@
     .catch(t.step_func(reason => {
       assert_unreached(reason);
     }));
-  }, 'Legacy addStream(): Media stream stats references track stats');
+  }, 'Media stream stats references track stats');
 
   async_test(t => {
     const caller = new RTCPeerConnection();
diff --git a/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-encodings.html b/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-encodings.html
index b446dde230ef..b8ae4e4c187c 100644
--- a/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-encodings.html
+++ b/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-encodings.html
@@ -48,6 +48,7 @@
         RTCDtxStatus        dtx;
         boolean             active;
         RTCPriorityType     priority;
+        RTCPriorityType     networkPriority;
         unsigned long       ptime;
         unsigned long       maxBitrate;
         double              maxFramerate;
@@ -146,6 +147,7 @@
         dtx: 'enabled',
         active: false,
         priority: 'low',
+        networkPriority: 'low',
         ptime: 5,
         maxBitrate: 8,
         maxFramerate: 25,
@@ -161,6 +163,7 @@
     assert_equals(encoding.dtx, 'enabled');
     assert_equals(encoding.active, false);
     assert_equals(encoding.priority, 'low');
+    assert_equals(encoding.networkPriority, 'low');
     assert_equals(encoding.ptime, 5);
     assert_equals(encoding.maxBitrate, 8);
     assert_equals(encoding.maxFramerate, 25);
@@ -339,6 +342,9 @@
   test_modified_encoding('audio', 'priority', 'very-low', 'high',
     'setParameters() with modified encoding.priority should succeed');
 
+  test_modified_encoding('audio', 'networkPriority', 'very-low', 'high',
+    'setParameters() with modified encoding.networkPriority should succeed');
+
   test_modified_encoding('audio', 'ptime', 2, 4,
     'setParameters() with modified encoding.ptime should succeed');
 
diff --git a/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-helper.js b/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-helper.js
index c4105decdfcb..8f7c85df475f 100644
--- a/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-helper.js
+++ b/tests/wpt/web-platform-tests/webrtc/RTCRtpParameters-helper.js
@@ -142,6 +142,7 @@ function validateRtpParameters(param) {
     RTCDtxStatus        dtx;
     boolean             active;
     RTCPriorityType     priority;
+    RTCPriorityType     networkPriority;
     unsigned long       ptime;
     unsigned long       maxBitrate;
     double              maxFramerate;
@@ -171,6 +172,8 @@ function validateEncodingParameters(encoding) {
   assert_optional_boolean_field(encoding, 'active');
   assert_optional_enum_field(encoding, 'priority',
     ['very-low', 'low', 'medium', 'high']);
+  assert_optional_enum_field(encoding, 'networkPriority',
+    ['very-low', 'low', 'medium', 'high']);
 
   assert_optional_unsigned_int_field(encoding, 'ptime');
   assert_optional_unsigned_int_field(encoding, 'maxBitrate');
diff --git a/tests/wpt/web-platform-tests/webrtc/legacy/RTCPeerConnection-addStream.https.html b/tests/wpt/web-platform-tests/webrtc/legacy/RTCPeerConnection-addStream.https.html
new file mode 100644
index 000000000000..5a35ebc53b8d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/webrtc/legacy/RTCPeerConnection-addStream.https.html
@@ -0,0 +1,74 @@
+<!doctype html>
+<meta charset=utf-8>
+<meta name="timeout" content="long">
+<title>RTCPeerConnection legacy addStream</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../RTCPeerConnection-helper.js"></script>
+<script src="../RTCStats-helper.js"></script>
+<script src="../dictionary-helper.js"></script>
+<script>
+  'use strict';
+
+  // The following helper functions are called from RTCPeerConnection-helper.js:
+  //   getUserMediaTracksAndStreams
+
+  // The following helper functions are called from RTCStats-helper.js
+  // (depends on dictionary-helper.js):
+  //   validateRtcStats
+
+  // TODO(hbos): addStream() is legacy API not in the spec. Based on discussion
+  // whether to standardize in legacy section, consider removing this test or
+  // keeping it until addTrack() has wide support.
+  // https://github.com/w3c/webrtc-pc/issues/1705
+  // https://github.com/w3c/webrtc-pc/issues/1125
+  async_test(t => {
+    const pc = new RTCPeerConnection();
+    t.add_cleanup(() => pc.close());
+    let track;
+    let stream;
+    return getUserMediaTracksAndStreams(1)
+    .then(t.step_func(([tracks, streams]) => {
+      track = tracks[0];
+      stream = streams[0];
+      stream.addTrack(track);
+      pc.addStream(stream);
+      return pc.createOffer();
+    }))
+    .then(t.step_func(offer => {
+      return pc.setLocalDescription(offer);
+    }))
+    .then(t.step_func(() => {
+      return pc.getStats();
+    }))
+    .then(t.step_func(report => {
+      let trackStats = findStatsByTypeAndId(report, 'track', track.id);
+      let streamStats = findStatsByTypeAndId(report, 'stream', stream.id);
+      assert_true(trackStats != null && streamStats != null,
+                  'Has stats for track and stream');
+      assert_array_equals(streamStats.trackIds, [ trackStats.id ],
+                          'streamStats.trackIds == [ trackStats.id ]');
+      validateRtcStats(report, trackStats);
+      validateRtcStats(report, streamStats);
+      t.done();
+    }))
+    .catch(t.step_func(reason => {
+      assert_unreached(reason);
+    }));
+  }, 'Legacy addStream(): Media stream stats references track stats');
+
+  function findStatsByTypeAndId(report, type, identifier) {
+    return findStats(report, stats => {
+      return stats.type == type && stats[type + 'Identifier'] == identifier;
+    });
+  }
+
+  function findStats(report, findFunc) {
+    for (let it = report.values(), n = it.next(); !n.done; n = it.next()) {
+      if (findFunc(n.value))
+        return n.value;
+    }
+    return null;
+  }
+
+</script>
diff --git a/tests/wpt/web-platform-tests/webrtc/no-media-call.html b/tests/wpt/web-platform-tests/webrtc/no-media-call.html
index 0f2e2a33e62b..10933fae4c39 100644
--- a/tests/wpt/web-platform-tests/webrtc/no-media-call.html
+++ b/tests/wpt/web-platform-tests/webrtc/no-media-call.html
@@ -1,7 +1,4 @@
 <!doctype html>
-<!--
-This test uses the legacy callback API with no media, and thus does not require fake media devices.
--->
 
 <html>
 <head>
@@ -37,7 +34,6 @@ <h2>iceConnectionState info</h2>
 
     var parsedOffer = new RTCSessionDescription({ type: 'offer',
                                                   sdp: offerSdp });
-    // These functions use the legacy interface extensions to RTCPeerConnection.
     gSecondConnection.setRemoteDescription(parsedOffer).then(
       function() {
         gSecondConnection.createAnswer().then(onAnswerCreated,