Use ChildThreadImpl::thread_safe_sender in font proxy if available

content/renderer/renderer_main_platform_delegate_win.cc

Index: content/renderer/renderer_main_platform_delegate_win.cc
diff --git a/content/renderer/renderer_main_platform_delegate_win.cc b/content/renderer/renderer_main_platform_delegate_win.cc
index 20efc6dc0319238ce80218cdc6977775b375d2c2..cf00ca2d62f87e330fe7dbb97c9cb3b3e5c5334c 100644
--- a/content/renderer/renderer_main_platform_delegate_win.cc
+++ b/content/renderer/renderer_main_platform_delegate_win.cc
@@ -30,6 +30,16 @@
 
 namespace content {
 
+namespace {
+
+// Helper function to cast RenderThread to IPC::Sender so we can Bind()
+// it.
+IPC::Sender* GetRenderThreadSender() {
+  return RenderThread::Get();
+}
+
+}  // namespace
+
 RendererMainPlatformDelegate::RendererMainPlatformDelegate(
     const MainFunctionParams& parameters)
     : parameters_(parameters) {}
@@ -53,7 +63,7 @@ void RendererMainPlatformDelegate::PlatformInitialize() {
     // is disabled, we don't have to make this dummy call.
     std::unique_ptr<icu::TimeZone> zone(icu::TimeZone::createDefault());
 
-    InitializeDWriteFontProxy();
+    InitializeDWriteFontProxy(base::Bind(&GetRenderThreadSender));
   }
   // TODO(robliao): This should use WebScreenInfo. See http://crbug.com/604555.
   blink::WebFontRendering::setDeviceScaleFactor(display::win::GetDPIScale());