Added purge method to SimpleFontData and PlatformFontData.

third_party/WebKit/Source/platform/fonts/SimpleFontData.cpp

 /*
  * Copyright (C) 2005, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov
  *
  * 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.
@@ skipping 429 matching lines @@
     for (unsigned i = 0; i < length; i++) {
         if (glyphs[i]) {
             pageToFill->setGlyphDataForIndex(offset + i, glyphs[i], this);
             haveGlyphs = true;
         }
     }
 
     return haveGlyphs;
 }
 
+void SimpleFontData::purgeMemory()
+{
+    m_glyphToBoundsMap.reset(nullptr);
+    m_platformData.purgeMemory();
+}
+
 } // namespace blink