Font fallback for UI

ui/gfx/platform_font_win.h

Index: ui/gfx/platform_font_win.h
diff --git a/ui/gfx/platform_font_win.h b/ui/gfx/platform_font_win.h
index 1cb0c9992f25b385fd9698680017c65e2aa2f07d..87bc4bbdc58c8fb903e0a705a23043e61af7a9a3 100644
--- a/ui/gfx/platform_font_win.h
+++ b/ui/gfx/platform_font_win.h
@@ -15,9 +15,16 @@
 #include "ui/gfx/platform_font.h"
 
 struct IDWriteFactory;
+struct IDWriteFont;
 
 namespace gfx {
 
+// Returns the family name for the |IDWriteFont| interface passed in.
+// The family name is returned in the |family_name_ret| parameter.
+// Returns S_OK on success.
+HRESULT GetFamilyNameFromDirectWriteFont(IDWriteFont* dwrite_font,
+                                         base::string16* family_name_ret);
+
 class GFX_EXPORT PlatformFontWin : public PlatformFont {
  public:
   PlatformFontWin();