cc: Poll for state that triggers draws (synchronous compositor only)

cc/scheduler/scheduler.h

Index: cc/scheduler/scheduler.h
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index 9c3ad538730dea53db93774dbe6bef71ff9c61f8..e740eb7c078c6399aa47e2a9b46195f45f1d0ee5 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -98,6 +98,7 @@ class CC_EXPORT Scheduler {
   base::TimeTicks LastBeginFrameOnImplThreadTime();
 
   void BeginFrame(const BeginFrameArgs& args);
+  void PollForAnticipatedDrawTriggers();
 
   scoped_ptr<base::Value> StateAsValue() {
     return state_machine_.AsValue().Pass();
@@ -120,6 +121,7 @@ class CC_EXPORT Scheduler {
   bool last_set_needs_begin_frame_;
   bool has_pending_begin_frame_;
   BeginFrameArgs last_begin_frame_args_;
+  base::CancelableClosure poll_for_draw_triggers_closure_;
 
   SchedulerStateMachine state_machine_;
   bool inside_process_scheduled_actions_;