Add more missing closing namespace comments.

third_party/WebKit/Source/core/layout/LayoutScrollbar.cpp

 /*
  * Copyright (C) 2008, 2009 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 349 matching lines @@
     partLayoutObject->layout();
     return orientation() == HorizontalScrollbar ? partLayoutObject->size().width() : partLayoutObject->size().height();
 }
 
 void LayoutScrollbar::invalidateDisplayItemClientsOfScrollbarParts(const LayoutBoxModelObject& paintInvalidationContainer)
 {
     for (auto& part : m_parts)
         part.value->invalidateDisplayItemClientsIncludingNonCompositingDescendants(&paintInvalidationContainer, PaintInvalidationScroll);
 }
 
-}
+} // namespace blink