Cleanup namespace usage in platform/graphics/[G-S]*

Source/platform/graphics/ReplayingCanvas.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 276 matching lines @@
 
     return this->SkCanvas::willSaveLayer(bounds, paint, flags);
 }
 
 void ReplayingCanvas::willRestore()
 {
     AutoReplayer replayer(this);
     this->SkCanvas::willRestore();
 }
 
-}
+} // namespace blink