Add plumbing in blink to allow overriding the default font collection.

third_party/WebKit/public/web/win/WebFontRendering.h

 // Copyright 2014 Google Inc. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebFontRendering_h
 #define WebFontRendering_h
 
 #include "public/platform/WebCommon.h"
+#include <RefPtr.h>
 #include <SkFontHost.h>
+#include <SkFontMgr.h>
 
 class SkTypeface;
 struct IDWriteFactory;
 
 namespace blink {
 
 class WebFontRendering {
 public:
     BLINK_EXPORT static void setUseDirectWrite(bool);
     BLINK_EXPORT static void setDirectWriteFactory(IDWriteFactory*);
+    BLINK_EXPORT static void setSkiaFontManager(const skia::RefPtr<SkFontMgr>&);
     BLINK_EXPORT static void setDeviceScaleFactor(float);
     BLINK_EXPORT static void setUseSubpixelPositioning(bool);
     BLINK_EXPORT static void addSideloadedFontForTesting(SkTypeface*);
     BLINK_EXPORT static void setMenuFontMetrics(const wchar_t* familyName, int32_t fontHeight);
     BLINK_EXPORT static void setSmallCaptionFontMetrics(const wchar_t* familyName, int32_t fontHeight);
     BLINK_EXPORT static void setStatusFontMetrics(const wchar_t* familyName, int32_t fontHeight);
     BLINK_EXPORT static void setLCDOrder(SkFontHost::LCDOrder);
     BLINK_EXPORT static void setLCDOrientation(SkFontHost::LCDOrientation);
 };
 
 } // namespace blink
 
 #endif