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

third_party/WebKit/Source/platform/fonts/FontCache.h

Index: third_party/WebKit/Source/platform/fonts/FontCache.h
diff --git a/third_party/WebKit/Source/platform/fonts/FontCache.h b/third_party/WebKit/Source/platform/fonts/FontCache.h
index 1b83f7de4b67e8da6b8d81a40b1c935b0e982c66..28f0364a3c8daf5c05459967e02094661a475d8e 100644
--- a/third_party/WebKit/Source/platform/fonts/FontCache.h
+++ b/third_party/WebKit/Source/platform/fonts/FontCache.h
@@ -46,6 +46,7 @@
 
 #if OS(WIN)
 #include "SkFontMgr.h"
+#include "skia/ext/refptr.h"
 struct IDWriteFactory;
 #endif
 
@@ -107,7 +108,8 @@ public:
     static bool useDirectWrite() { return s_useDirectWrite; }
     static float deviceScaleFactor() { return s_deviceScaleFactor; }
     static void setUseDirectWrite(bool useDirectWrite) { s_useDirectWrite = useDirectWrite; }
-    static void setDirectWriteFactory(IDWriteFactory* factory) { s_directWriteFactory = factory; }
+    static void setFontManager(const skia::RefPtr<SkFontMgr>&);
+    static void setDirectWriteFactory(IDWriteFactory*);
     static void setDeviceScaleFactor(float deviceScaleFactor) { s_deviceScaleFactor = deviceScaleFactor; }
     static void setUseSubpixelPositioning(bool useSubpixelPositioning) { s_useSubpixelPositioning = useSubpixelPositioning; }
     static void addSideloadedFontForTesting(SkTypeface*);
@@ -176,9 +178,10 @@ private:
     int m_purgePreventCount;
 
 #if OS(WIN)
-    OwnPtr<SkFontMgr> m_fontManager;
+    skia::RefPtr<SkFontMgr> m_fontManager;

[jbroman, 2016/01/21 15:51:31]

drive-by: Blink currently uses WTF::RefPtr for Skia objects, rather than
skia::RefPtr.

[Ilya Kulshin, 2016/01/21 20:59:22]

Done. I switched back to raw pointers for the public API, since I didn't want to
force yet another smart pointer class on callers. Switched to WTF::RefPtr
elsewhere.

     static bool s_useDirectWrite;
     static IDWriteFactory* s_directWriteFactory;
+    static SkFontMgr* s_fontManager;
     static float s_deviceScaleFactor;
     static bool s_useSubpixelPositioning;
     static HashMap<String, RefPtr<SkTypeface>>* s_sideloadedFonts;