Implement direct write fallback proxy

content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.cc

Index: content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.cc
diff --git a/content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.cc b/content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.cc
index 58d10551b9b268b36072ae0faa2c553fe285acc5..e7a2f2afe6f3cf5a9aba5847a9f0c65f772c570c 100644
--- a/content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.cc
+++ b/content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.cc
@@ -12,6 +12,7 @@
 #include "base/win/iat_patch_function.h"
 #include "base/win/windows_version.h"
 #include "content/child/dwrite_font_proxy/dwrite_font_proxy_win.h"
+#include "content/child/dwrite_font_proxy/font_fallback_win.h"
 #include "content/child/font_warmup_win.h"
 #include "skia/ext/fontmgr_default_win.h"
 #include "third_party/WebKit/public/web/win/WebFontRendering.h"
@@ -71,8 +72,15 @@ void InitializeDWriteFontProxy() {
         &g_font_collection, factory.Get(), g_sender_override);
   }
 
-  sk_sp<SkFontMgr> skia_font_manager(
-      SkFontMgr_New_DirectWrite(factory.Get(), g_font_collection.Get()));
+  mswr::ComPtr<IDWriteFontFallback> font_fallback;
+  mswr::ComPtr<IDWriteFactory2> factory2;
+  if (SUCCEEDED(factory.As(&factory2)) && factory2.Get()) {
+    mswr::MakeAndInitialize<FontFallback>(
+        &font_fallback, g_font_collection.Get(), g_sender_override);
+  }
+
+  sk_sp<SkFontMgr> skia_font_manager(SkFontMgr_New_DirectWrite(
+      factory.Get(), g_font_collection.Get(), font_fallback.Get()));
   blink::WebFontRendering::setSkiaFontManager(skia_font_manager.get());
 
   // Add an extra ref for SetDefaultSkiaFactory, which keeps a ref but doesn't