Create a new action triggered when a BeginMainFrame is not expected before vsync

cc/scheduler/scheduler_state_machine.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_SCHEDULER_SCHEDULER_STATE_MACHINE_H_
 #define CC_SCHEDULER_SCHEDULER_STATE_MACHINE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 105 matching lines @@
     ACTION_SEND_BEGIN_MAIN_FRAME,
     ACTION_COMMIT,
     ACTION_ACTIVATE_SYNC_TREE,
     ACTION_PERFORM_IMPL_SIDE_INVALIDATION,
     ACTION_DRAW_IF_POSSIBLE,
     ACTION_DRAW_FORCED,
     ACTION_DRAW_ABORT,
     ACTION_BEGIN_COMPOSITOR_FRAME_SINK_CREATION,
     ACTION_PREPARE_TILES,
     ACTION_INVALIDATE_COMPOSITOR_FRAME_SINK,
+    ACTION_DO_SHORT_IDLE_WORK,

[Sami, 2017/03/30 15:30:36]

ACTION_NOTIFY_BEGIN_MAIN_FRAME_NOT_SENT

[Dan Elphick, 2017/04/06 16:10:17]

Done.

   };
   static const char* ActionToString(Action action);
 
   std::unique_ptr<base::trace_event::ConvertableToTraceFormat> AsValue() const;
   void AsValueInto(base::trace_event::TracedValue* dict) const;
 
   Action NextAction() const;
   void WillSendBeginMainFrame();
+  void WillDoShortIdleWork();
   void WillCommit(bool commit_had_no_updates);
   void WillActivate();
   void WillDraw();
   void WillBeginCompositorFrameSinkCreation();
   void WillPrepareTiles();
   void WillInvalidateCompositorFrameSink();
   void WillPerformImplSideInvalidation();
 
   void DidDraw(DrawResult draw_result);
 
@@ skipping 167 matching lines @@
   // TODO(sunnyps): Rename this to ShouldAbortCurrentFrame or similar.
   bool PendingActivationsShouldBeForced() const;
 
   bool ShouldBeginCompositorFrameSinkCreation() const;
   bool ShouldDraw() const;
   bool ShouldActivatePendingTree() const;
   bool ShouldSendBeginMainFrame() const;
   bool ShouldCommit() const;
   bool ShouldPrepareTiles() const;
   bool ShouldInvalidateCompositorFrameSink() const;
+  bool ShouldDoShortIdleWork() const;
 
   void WillDrawInternal();
   void WillPerformImplSideInvalidationInternal();
   void DidDrawInternal(DrawResult draw_result);
 
   void UpdateBeginFrameSequenceNumbersForBeginFrame(uint32_t source_id,
                                                     uint64_t sequence_number);
   void UpdateBeginFrameSequenceNumbersForBeginFrameDeadline();
 
   const SchedulerSettings settings_;
@@ skipping 18 matching lines @@
   int commit_count_;
   int current_frame_number_;
   int last_frame_number_submit_performed_;
   int last_frame_number_draw_performed_;
   int last_frame_number_begin_main_frame_sent_;
   int last_frame_number_invalidate_compositor_frame_sink_performed_;
 
   // These are used to ensure that an action only happens once per frame,
   // deadline, etc.
   bool draw_funnel_;
-  bool send_begin_main_frame_funnel_;
+  bool did_send_begin_main_frame_for_current_frame_;
   bool invalidate_compositor_frame_sink_funnel_;
   bool impl_side_invalidation_funnel_;
+  bool did_do_idle_work_;

[Sami, 2017/03/30 15:30:37]

Let's also add a flag saying whether we did a commit in this frame and avoid
idling in that case.

[Dan Elphick, 2017/04/06 16:10:16]

Done.

   // prepare_tiles_funnel_ is "filled" each time PrepareTiles is called
   // and "drained" on each BeginImplFrame. If the funnel gets too full,
   // we start throttling ACTION_PREPARE_TILES such that we average one
   // PrepareTiles per BeginImplFrame.
   int prepare_tiles_funnel_;
 
   int consecutive_checkerboard_animations_;
   int pending_submit_frames_;
   int submit_frames_with_current_compositor_frame_sink_;
   bool needs_redraw_;
@@ skipping 24 matching lines @@
   bool previous_pending_tree_was_impl_side_;
   bool current_pending_tree_is_impl_side_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SchedulerStateMachine);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_STATE_MACHINE_H_