Introduce toHTMLCanvasElement

Source/core/rendering/RenderLayerBacking.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 57 matching lines @@
 namespace WebCore {
 
 using namespace HTMLNames;
 
 static bool hasBoxDecorationsOrBackgroundImage(const RenderStyle*);
 static IntRect clipBox(RenderBox* renderer);
 
 static inline bool isAcceleratedCanvas(RenderObject* renderer)
 {
     if (renderer->isCanvas()) {
-        HTMLCanvasElement* canvas = static_cast<HTMLCanvasElement*>(renderer->node());
+        HTMLCanvasElement* canvas = toHTMLCanvasElement(renderer->node());
         if (CanvasRenderingContext* context = canvas->renderingContext())
             return context->isAccelerated();
     }
     return false;
 }
 
 // Get the scrolling coordinator in a way that works inside RenderLayerBacking's destructor.
 static ScrollingCoordinator* scrollingCoordinatorFromLayer(RenderLayer* layer)
 {
     Page* page = layer->renderer()->frame()->page();
@@ skipping 311 matching lines @@
     if (isDirectlyCompositedImage())
         updateImageContents();
 
     if (renderer->isEmbeddedObject() && toRenderEmbeddedObject(renderer)->allowsAcceleratedCompositing()) {
         PluginView* pluginView = toPluginView(toRenderWidget(renderer)->widget());
         m_graphicsLayer->setContentsToMedia(pluginView->platformLayer());
     } else if (renderer->isVideo()) {
         HTMLMediaElement* mediaElement = toMediaElement(renderer->node());
         m_graphicsLayer->setContentsToMedia(mediaElement->platformLayer());
     } else if (isAcceleratedCanvas(renderer)) {
-        HTMLCanvasElement* canvas = static_cast<HTMLCanvasElement*>(renderer->node());
+        HTMLCanvasElement* canvas = toHTMLCanvasElement(renderer->node());
         if (CanvasRenderingContext* context = canvas->renderingContext())
             m_graphicsLayer->setContentsToCanvas(context->platformLayer());
         layerConfigChanged = true;
     }
     if (renderer->isRenderPart())
         layerConfigChanged = RenderLayerCompositor::parentFrameContentLayers(toRenderPart(renderer));
 
     return layerConfigChanged;
 }
 
@@ skipping 1464 matching lines @@
     info.addMember(m_childContainmentLayer, "childContainmentLayer");
     info.addMember(m_maskLayer, "maskLayer");
     info.addMember(m_layerForHorizontalScrollbar, "layerForHorizontalScrollbar");
     info.addMember(m_layerForVerticalScrollbar, "layerForVerticalScrollbar");
     info.addMember(m_layerForScrollCorner, "layerForScrollCorner");
     info.addMember(m_scrollingLayer, "scrollingLayer");
     info.addMember(m_scrollingContentsLayer, "scrollingContentsLayer");
 }
 
 } // namespace WebCore