Set CanvasResourceHost when canvas replaces its canvas2d layer bridge

TBR=junov@chromium.org

Bug: 807636, 807427
Change-Id: Ic5fe5abbf5deaed883c005280fd8418cf49ca9d2
Reviewed-on: https://chromium-review.googlesource.com/899962
Commit-Queue: Olivia Lai <xlai@chromium.org>
Reviewed-by: Mohammad Reza Zakerinasab <zakerinasab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534152}

third_party/WebKit/Source/core/html/canvas/HTMLCanvasElement.cpp

@@ -1558,6 +1558,7 @@ void HTMLCanvasElement::ReplaceExistingCanvas2DBuffer(
   RestoreCanvasMatrixClipStack(new_buffer->Canvas());
   new_buffer->DidRestoreCanvasMatrixClipStack(new_buffer->Canvas());
   canvas2d_bridge_ = std::move(new_buffer);
+  canvas2d_bridge_->SetCanvasResourceHost(this);
 }
 
 scoped_refptr<StaticBitmapImage> HTMLCanvasElement::NewImageSnapshot(

third_party/WebKit/Source/modules/canvas/canvas2d/CanvasRenderingContext2DTest.cpp

@@ -107,6 +107,9 @@ class CanvasRenderingContext2DTest : public ::testing::Test {
   DummyPageHolder& Page() const { return *dummy_page_holder_; }
   Document& GetDocument() const { return *document_; }
   HTMLCanvasElement& CanvasElement() const { return *canvas_element_; }
+  bool IsCanvasResourceHostSet(Canvas2DLayerBridge* bridge) {
+    return !!bridge->resource_host_;
+  }
   CanvasRenderingContext2D* Context2d() const {
     return static_cast<CanvasRenderingContext2D*>(
         CanvasElement().RenderingContext());
@@ -810,8 +813,11 @@ TEST_F(CanvasRenderingContext2DTest,
       .Times(1);
 
   EXPECT_TRUE(CanvasElement().Canvas2DBuffer()->IsAccelerated());
+  EXPECT_TRUE(IsCanvasResourceHostSet(CanvasElement().Canvas2DBuffer()));
+
   CanvasElement().DisableAcceleration(std::move(fake_deaccelerate_surface));
   EXPECT_FALSE(CanvasElement().Canvas2DBuffer()->IsAccelerated());
+  EXPECT_TRUE(IsCanvasResourceHostSet(CanvasElement().Canvas2DBuffer()));
 
   Mock::VerifyAndClearExpectations(surface_ptr);
 }