Add code to call skia's matchFamilyStyleCharacter API, which uses the

content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/child/dwrite_font_proxy/dwrite_font_proxy_init_win.h"
 
 #include <dwrite.h>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 69 matching lines @@
   }
 
   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
   // addref.
   skia_font_manager->ref();
   SetDefaultSkiaFactory(skia_font_manager.get());
+
+  // When IDWriteFontFallback is not available (prior to Win8.1) Skia will
+  // still attempt to use DirectWrite to determine fallback fonts (in
+  // SkFontMgr_DirectWrite::onMatchFamilyStyleCharacter), which will likely
+  // result in trying to load the system font collection. To avoid that and
+  // instead fall back on WebKit's fallback logic, we don't use Skia's font
+  // fallback if IDWriteFontFallback is not available.
+  // This flag can be removed when Win8.0 and earlier are no longer supported.
+  bool fallback_available = font_fallback.Get() != nullptr;
+  DCHECK_EQ(fallback_available,
+    base::win::GetVersion() > base::win::VERSION_WIN8);
+  blink::WebFontRendering::setUseSkiaFontFallback(fallback_available);
 }
 
 void UninitializeDWriteFontProxy() {
   if (g_font_collection)
     g_font_collection->Unregister();
 }
 
 void SetDWriteFontProxySenderForTesting(IPC::Sender* sender) {
   g_sender_override = sender;
 }
 
 }  // namespace content