Support sideloaded fonts for DirectWrite

Source/platform/fonts/FontCache.h

Index: Source/platform/fonts/FontCache.h
diff --git a/Source/platform/fonts/FontCache.h b/Source/platform/fonts/FontCache.h
index 8383a513762444ce2814f6a31b925d983805f4f5..0a556d0372e5fb1e21e9a6510a14c5dc4e2126d7 100644
--- a/Source/platform/fonts/FontCache.h
+++ b/Source/platform/fonts/FontCache.h
@@ -33,6 +33,7 @@
 #include <limits.h>
 #include "platform/PlatformExport.h"
 #include "wtf/Forward.h"
+#include "wtf/HashSet.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
 #include "wtf/Vector.h"
@@ -103,6 +104,7 @@ public:
     static void setUseDirectWrite(bool useDirectWrite) { s_useDirectWrite = useDirectWrite; }
     static void setDirectWriteFactory(IDWriteFactory* factory) { s_directWriteFactory = factory; }
     static void setUseSubpixelPositioning(bool useSubpixelPositioning) { s_useSubpixelPositioning = useSubpixelPositioning; }
+    static void addSideloadedFont(SkTypeface*);

[eae, 2014/04/12 10:51:33]

How about addSideloadedFontForTesting to discourage further use and make it
clear that it is not intended for widespread use?

[scottmg, 2014/04/12 15:42:39]

SG, Done.

 #endif
 
 #if ENABLE(OPENTYPE_VERTICAL)
@@ -154,6 +156,7 @@ private:
     static bool s_useDirectWrite;
     static IDWriteFactory* s_directWriteFactory;
     static bool s_useSubpixelPositioning;
+    static HashMap<String, SkTypeface*>* s_sideloadedFonts;
 #endif
 
 #if OS(MACOSX) || OS(ANDROID)