Make OffscreenCanvas animation in sync with its placeholder canvas's parent frame rate

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

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 20 matching lines @@
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptController.h"
 #include "core/HTMLNames.h"
 #include "core/InputTypeNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/fileapi/File.h"
+#include "core/frame/FrameHost.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLSelectElement.h"
 #include "core/html/ImageData.h"
 #include "core/html/canvas/CanvasAsyncBlobCreator.h"
 #include "core/html/canvas/CanvasContextCreationAttributes.h"
 #include "core/html/canvas/CanvasFontCache.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/html/canvas/CanvasRenderingContextFactory.h"
 #include "core/imagebitmap/ImageBitmapOptions.h"
 #include "core/layout/HitTestCanvasResult.h"
 #include "core/layout/LayoutHTMLCanvas.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/layout/compositing/PaintLayerCompositor.h"
+#include "core/page/ChromeClient.h"
 #include "core/paint/PaintLayer.h"
 #include "core/paint/PaintTiming.h"
 #include "platform/Histogram.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/Canvas2DImageBufferSurface.h"
 #include "platform/graphics/CanvasMetrics.h"
 #include "platform/graphics/ExpensiveCanvasHeuristicParameters.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/graphics/RecordingImageBufferSurface.h"
 #include "platform/graphics/StaticBitmapImage.h"
@@ skipping 1347 matching lines @@
 }
 
 String HTMLCanvasElement::getIdFromControl(const Element* element) {
   if (m_context)
     return m_context->getIdFromControl(element);
   return String();
 }
 
 void HTMLCanvasElement::createLayer() {
   DCHECK(!m_surfaceLayerBridge);
-  m_surfaceLayerBridge = WTF::wrapUnique(new CanvasSurfaceLayerBridge(this));
-  // Creates a placeholder layer first before Surface is created.
-  m_surfaceLayerBridge->createSolidColorLayer();
+  LocalFrame* frame = document().frame();
+  WebLayerTreeView* layerTreeView = nullptr;
+  // TODO(xlai): Ensure OffscreenCanvas commit() is still functional when a
+  // frame-less HTML canvas's document is reparenting under another frame.
+  // See crbug.com/683172.
+  if (frame) {
+    layerTreeView = frame->host()->chromeClient().getWebLayerTreeView(frame);
+    m_surfaceLayerBridge =
+        WTF::wrapUnique(new CanvasSurfaceLayerBridge(this, layerTreeView));
+    // Creates a placeholder layer first before Surface is created.
+    m_surfaceLayerBridge->createSolidColorLayer();
+  }
 }
 
 void HTMLCanvasElement::OnWebLayerReplaced() {
   setNeedsCompositingUpdate();
 }
 
 }  // namespace blink