Cleanup namespace usage in platform/fonts/.

Source/platform/fonts/FontCacheKey.h

 /*
  * 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:
  *
  * 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
@@ skipping 93 matching lines @@
     static bool equal(const FontCacheKey& a, const FontCacheKey& b)
     {
         return a == b;
     }
 
     static const bool safeToCompareToEmptyOrDeleted = true;
 };
 
 struct FontCacheKeyTraits : WTF::SimpleClassHashTraits<FontCacheKey> { };
 
-}
+} // namespace blink
 
 #endif // FontCacheKey_h