Add DisplayScheduler for Surfaces

cc/scheduler/scheduler_state_machine.h

Index: cc/scheduler/scheduler_state_machine.h
diff --git a/cc/scheduler/scheduler_state_machine.h b/cc/scheduler/scheduler_state_machine.h
index cf29ca9b6a53ec89a43c1b20e905e9c4792dff8f..5787ec9e5c625802befe827c167fe7c56b7eb445 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -126,6 +126,10 @@ class CC_EXPORT SchedulerStateMachine {
   // to make progress.
   bool BeginFrameNeeded() const;
 
+  // Notifies the statme machine that the Scheduler skipped a BeginImplFrame
+  // so the state machine can reset associated state.
+  void DidSkipBeginImplFrameToReduceLatency();
+
   // Indicates that the system has entered and left a BeginImplFrame callback.
   // The scheduler will not draw more than once in a given BeginImplFrame
   // callback nor send more than one BeginMainFrame message.
@@ -145,6 +149,10 @@ class CC_EXPORT SchedulerStateMachine {
   // impl thread to draw, it is in a high latency mode.
   bool MainThreadIsInHighLatencyMode() const;
 
+  bool last_swap_ack_came_after_begin_impl_frame() const {
+    return last_swap_ack_came_after_begin_impl_frame_;
+  }
+
   // Indicates whether the LayerTreeHostImpl is visible.
   void SetVisible(bool visible);
   bool visible() const { return visible_; }
@@ -317,6 +325,7 @@ class CC_EXPORT SchedulerStateMachine {
   int consecutive_checkerboard_animations_;
   int max_pending_swaps_;
   int pending_swaps_;
+  bool last_swap_ack_came_after_begin_impl_frame_;
   bool needs_redraw_;
   bool needs_animate_;
   bool needs_prepare_tiles_;