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

Source/core/rendering/RenderVideo.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 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 258 matching lines @@
     return RenderMedia::offsetWidth();
 }
 
 LayoutUnit RenderVideo::offsetHeight() const
 {
     if (const RenderBlock* block = rendererPlaceholder(this))
         return block->offsetHeight();
     return RenderMedia::offsetHeight();
 }
 
+CompositingReasons RenderVideo::additionalCompositingReasons(CompositingTriggerFlags triggers) const
+{
+    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled()) {
+        HTMLMediaElement* media = toHTMLMediaElement(node());
+        if (media->isFullscreen())
+            return CompositingReasonVideo;
+    }
+
+    if ((triggers & VideoTrigger) && shouldDisplayVideo() && supportsAcceleratedRendering())
+        return CompositingReasonVideo;
+
+    return CompositingReasonNone;
+}
+
 } // namespace WebCore