Add more missing closing namespace comments.

third_party/WebKit/Source/platform/graphics/paint/DrawingDisplayItem.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 
 #include "platform/graphics/GraphicsContext.h"
 #include "public/platform/WebDisplayItemList.h"
 
 #if ENABLE(ASSERT)
@@ skipping 95 matching lines @@
         canvas.drawPicture(picture.get(), nullptr, &diffPaint);
         return bitmapIsAllZero(bitmap);
     }
     default:
         ASSERT_NOT_REACHED();
     }
     return false;
 }
 #endif // ENABLE(ASSERT)
 
-}
+} // namespace blink