Cleanup namespace usage in platform/fonts/.

Source/platform/fonts/FontPlatformData.cpp

 /*
  * Copyright (C) 2011 Brent Fulgham
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 101 matching lines @@
     m_syntheticOblique = other.m_syntheticOblique;
     m_orientation = other.m_orientation;
     m_size = other.m_size;
     m_widthVariant = other.m_widthVariant;
     m_isColorBitmapFont = other.m_isColorBitmapFont;
     m_isCompositeFontReference = other.m_isCompositeFontReference;
 
     return platformDataAssign(other);
 }
 
-}
+} // namespace blink