cc: Allow sending BeginMainFrame before draw or activation

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 ab45c3e1de63ff13d0977086dc235484e5586d79..ed3d43cba1516876abe170c568b0d941f8f19ecb 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -988,8 +988,6 @@ void ThreadProxy::StartCommitOnImplThread(
     CompletionEvent* completion,
     ResourceUpdateQueue* raw_queue,
     scoped_refptr<ContextProvider> offscreen_context_provider) {
-  scoped_ptr<ResourceUpdateQueue> queue(raw_queue);
-
   TRACE_EVENT0("cc", "ThreadProxy::StartCommitOnImplThread");
   DCHECK(!impl().commit_completion_event);
   DCHECK(IsImplThread() && IsMainThreadBlocked());
@@ -1003,6 +1001,8 @@ void ThreadProxy::StartCommitOnImplThread(
     return;
   }
 
+  scoped_ptr<ResourceUpdateQueue> queue(raw_queue);
+
   if (offscreen_context_provider.get())
     offscreen_context_provider->BindToCurrentThread();
   impl().layer_tree_host_impl->SetOffscreenContextProvider(
@@ -1470,6 +1470,10 @@ void ThreadProxy::InitializeImplOnImplThread(CompletionEvent* completion) {
       layer_tree_host()->CreateLayerTreeHostImpl(this);
   const LayerTreeSettings& settings = layer_tree_host()->settings();
   SchedulerSettings scheduler_settings;
+  scheduler_settings.start_commit_before_draw_enabled =
+      settings.start_commit_before_draw_enabled;
+  scheduler_settings.start_commit_before_activate_enabled =
+      settings.start_commit_before_activate_enabled;
   scheduler_settings.impl_side_painting = settings.impl_side_painting;
   scheduler_settings.timeout_and_draw_when_animation_checkerboards =
       settings.timeout_and_draw_when_animation_checkerboards;