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

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 e7a2f2afe6f3cf5a9aba5847a9f0c65f772c570c..da083233fb2f7fccb082bb85c9d33e77b69249e9 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
@@ -87,6 +87,18 @@ void InitializeDWriteFontProxy() {
   // 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() {