Add plumbing in blink to allow overriding the skia font manager.

third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Computer, Inc.
  * Copyright (c) 2006, 2007, 2008, 2009, 2012 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.
@@ skipping 79 matching lines @@
 // static
 void FontCache::setStatusFontMetrics(const wchar_t* familyName, int32_t fontHeight)
 {
     s_statusFontFamilyName = new AtomicString(familyName);
     s_statusFontHeight = ensureMinimumFontHeightIfNeeded(fontHeight);
 }
 
 FontCache::FontCache()
     : m_purgePreventCount(0)
 {
-    SkFontMgr* fontManager;
-
-    if (s_useDirectWrite) {
-        fontManager = SkFontMgr_New_DirectWrite(s_directWriteFactory);
-        s_useSubpixelPositioning = true;
+    if (s_fontManager) {
+        m_fontManager = s_fontManager;
+    } else if (s_useDirectWrite) {
+        m_fontManager = adoptRef(SkFontMgr_New_DirectWrite());
     } else {
-        fontManager = SkFontMgr_New_GDI();
-        // Subpixel text positioning is not supported by the GDI backend.
-        s_useSubpixelPositioning = false;
+        m_fontManager = adoptRef(SkFontMgr_New_GDI());
     }
 
-    ASSERT(fontManager);
-    m_fontManager = adoptPtr(fontManager);
+    // Subpixel text positioning is only supported by the DirectWrite backend (not GDI).
+    s_useSubpixelPositioning = s_useDirectWrite;
+
+    ASSERT(m_fontManager.get());
 }
 
 void FontCache::acceptLanguagesChanged(const String&)
 {
     // TODO(kojii): Take acceptLanguages into account for ambiguos scripts.
 }
 
 // Given the desired base font, this will create a SimpleFontData for a specific
 // font that can be used to render the given range of characters.
 PassRefPtr<SimpleFontData> FontCache::fallbackFontForCharacter(
@@ skipping 301 matching lines @@
         if (typefacesMatchesFamily(tf.get(), family)) {
             result->setMinSizeForSubpixel(minSizeForSubpixelForFont);
             break;
         }
     }
 
     return result.release();
 }
 
 } // namespace blink