CompositingReasonFinder should use a virtual function instead of a nest of branches

Source/core/rendering/RenderHTMLCanvas.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 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 93 matching lines @@
     LayoutSize oldSize = size();
     updateLogicalWidth();
     updateLogicalHeight();
     if (oldSize == size())
         return;
 
     if (!selfNeedsLayout())
         setNeedsLayout();
 }
 
+CompositingReasons RenderHTMLCanvas::additionalCompositingReasons(CompositingTriggerFlags triggers) const
+{
+    if (!(triggers & CanvasTrigger))
+        return CompositingReasonNone;
+
+    HTMLCanvasElement* canvas = toHTMLCanvasElement(node());
+    if (canvas->renderingContext() && canvas->renderingContext()->isAccelerated())
+        return CompositingReasonCanvas;
+
+    return CompositingReasonNone;
+}
+
 } // namespace WebCore