Cleanup namespace usage in Source/core/rendering

Source/core/rendering/GraphicsContextAnnotator.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 2013 Samsung Electronics. 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.
@@ skipping 122 matching lines @@
     m_context = paintInfo.context;
     m_context->beginAnnotation(annotations);
 }
 
 void GraphicsContextAnnotator::finishAnnotation()
 {
     ASSERT(m_context);
     m_context->endAnnotation();
 }
 
-}
+} // namespace blink