Added purge method to SimpleFontData and PlatformFontData.

third_party/WebKit/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 328 matching lines @@
 
     const size_t tableSize = m_typeface->getTableSize(tag);
     if (tableSize) {
         Vector<char> tableBuffer(tableSize);
         m_typeface->getTableData(tag, 0, tableSize, &tableBuffer[0]);
         buffer = SharedBuffer::adoptVector(tableBuffer);
     }
     return buffer.release();
 }
 
+void FontPlatformData::purgeMemory()
+{
+    m_harfBuzzFace = nullptr;
+}
+
 } // namespace blink