Re-land: Make 2D canvas smarter about chosing whether or not to use GPU acceleration

third_party/WebKit/Source/core/html/HTMLCanvasElement.h

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
index 7173957a4058858e351c7dfdc0b3cc0cc92042ce..2f786efeb103090cef8095a01b68d8140d6832aa 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
@@ -132,7 +132,7 @@ public:
 
     void ensureUnacceleratedImageBuffer();
     ImageBuffer* buffer() const;
-    PassRefPtr<Image> copiedImage(SourceDrawingBuffer) const;
+    PassRefPtr<Image> copiedImage(SourceDrawingBuffer, AccelerationHint) const;
     void clearCopiedImage();
 
     SecurityOrigin* securityOrigin() const;
@@ -151,6 +151,8 @@ public:
 
     bool shouldBeDirectComposited() const;
 
+    void prepareSurfaceForPaintingIfNeeded() const;
+
     const AtomicString imageSourceURL() const override;
 
     InsertionNotificationRequest insertedInto(ContainerNode*) override;
@@ -159,7 +161,7 @@ public:
     void didChangeVisibilityState(PageVisibilityState) override;
 
     // CanvasImageSource implementation
-    PassRefPtr<Image> getSourceImageForCanvas(SourceImageStatus*) const override;
+    PassRefPtr<Image> getSourceImageForCanvas(SourceImageStatus*, AccelerationHint) const override;
     bool wouldTaintOrigin(SecurityOrigin*) const override;
     FloatSize elementSize() const override;
     bool isCanvasElement() const override { return true; }