Moving GraphicsContext and dependencies from core to platform.

Source/platform/exported/linux/WebFontInfo.cpp

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 188 matching lines @@
     }
 
     // FontConfig doesn't provide parameters to configure whether subpixel
     // positioning should be used or not, so we just use a global setting.
     out->useSubpixelPositioning = useSubpixelPositioning;
 
     FcPatternDestroy(match);
 }
 
 } // namespace blink