From 70e12ae8a8f818582b172d69b9bd18a895ad04ec Mon Sep 17 00:00:00 2001
From: Kartikaya Gupta <kgupta@mozilla.com>
Date: Fri, 14 Dec 2018 10:19:32 -0500
Subject: [PATCH] Clear clip_node_instances on new frame builds.

The clip node instances are rebuilt for each frame built from a given
scene, but are not cleared until a new scene is built. So if a given
scene builds many frames, the clip node instances just accumulate and
eat up memory.

Fixes #3416.
---
 webrender/src/clip.rs          | 5 +++++
 webrender/src/frame_builder.rs | 1 +
 2 files changed, 6 insertions(+)

diff --git a/webrender/src/clip.rs b/webrender/src/clip.rs
index 25ff86c759..87c46a8cf9 100644
--- a/webrender/src/clip.rs
+++ b/webrender/src/clip.rs
@@ -696,6 +696,11 @@ impl ClipStore {
         })
     }
 
+    pub fn clear_old_instances(&mut self) {
+        self.clip_node_instances.clear();
+    }
+
+
     /// Walk the clip chain of a primitive, and calculate a minimal
     /// local clip rect for the primitive.
     #[allow(dead_code)]
diff --git a/webrender/src/frame_builder.rs b/webrender/src/frame_builder.rs
index 6b41bf7cb6..d5ac824024 100644
--- a/webrender/src/frame_builder.rs
+++ b/webrender/src/frame_builder.rs
@@ -407,6 +407,7 @@ impl FrameBuilder {
             scene_properties,
             Some(&mut transform_palette),
         );
+        self.clip_store.clear_old_instances();
 
         let mut render_tasks = RenderTaskTree::new(stamp.frame_id());
         let mut surfaces = Vec::new();