cc: Defer first OutputSurface creation until client is ready

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 89a6773ef38d8bd94fff36ecaf528e046124a866..82cc7bac3dc6b268990a0b311fd075b11b6b68aa 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -201,8 +201,12 @@ bool ThreadProxy::IsStarted() const {
   return started_;
 }
 
-void ThreadProxy::SetLayerTreeHostClientReady() {
+void ThreadProxy::SetLayerTreeHostClientReady(
+    scoped_ptr<OutputSurface> first_output_surface) {
   TRACE_EVENT0("cc", "ThreadProxy::SetLayerTreeHostClientReady");
+  DCHECK(first_output_surface);
+  first_output_surface_ = first_output_surface.Pass();
+
   Proxy::ImplThreadTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&ThreadProxy::SetLayerTreeHostClientReadyOnImplThread,
@@ -622,10 +626,9 @@ ThreadProxy::contents_texture_manager_on_impl_thread() {
   return contents_texture_manager_unsafe_;
 }
 
-void ThreadProxy::Start(scoped_ptr<OutputSurface> first_output_surface) {
+void ThreadProxy::Start() {
   DCHECK(IsMainThread());
   DCHECK(Proxy::HasImplThread());
-  DCHECK(first_output_surface);
 
   // Create LayerTreeHostImpl.
   DebugScopedSetMainThreadBlocked main_thread_blocked(this);
@@ -638,7 +641,6 @@ void ThreadProxy::Start(scoped_ptr<OutputSurface> first_output_surface) {
   completion.Wait();
 
   main_thread_weak_ptr_ = weak_factory_.GetWeakPtr();
-  first_output_surface_ = first_output_surface.Pass();
 
   started_ = true;
 }