Allow Blink to generate cc::FrameSinkId from RenderThread

content/renderer/renderer_blink_platform_impl.cc

Index: content/renderer/renderer_blink_platform_impl.cc
diff --git a/content/renderer/renderer_blink_platform_impl.cc b/content/renderer/renderer_blink_platform_impl.cc
index e038d2bc1108721538e3841aff4aa289a18a7e2b..1565487a846094790c515f0964eb7cbb31498767 100644
--- a/content/renderer/renderer_blink_platform_impl.cc
+++ b/content/renderer/renderer_blink_platform_impl.cc
@@ -618,6 +618,11 @@ WebString RendererBlinkPlatformImpl::databaseCreateOriginIdentifier(
       WebSecurityOriginToGURL(origin)));
 }
 
+cc::FrameSinkId RendererBlinkPlatformImpl::generateFrameSinkId() {
+  return cc::FrameSinkId(RenderThread::Get()->GetClientId(),
+                         RenderThread::Get()->GenerateRoutingID());
+}
+
 bool RendererBlinkPlatformImpl::isThreadedCompositingEnabled() {
   RenderThreadImpl* thread = RenderThreadImpl::current();
   // thread can be NULL in tests.