cc: Implement deadine scheduling disabled by default

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 ad2cf65c3e6c91f7d623af3b95b327f31473fef6..95566a408e044a3415ac4160a2a4e7b62bf65403 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -45,6 +45,18 @@ class CC_EXPORT SchedulerStateMachine {
   };
   static const char* OutputSurfaceStateToString(OutputSurfaceState state);
 
+  // Note: BeginFrameState will always cycle through all the states in order.
+  // Whether or not it actually waits or draws, it will at least try to wait in
+  // BEGIN_FRAME_STATE_DEADLINE_PENDING and try to draw in
+  // BEGIN_FRAME_STATE_INSIDE_DEADLINE
+  enum BeginFrameState {
+    BEGIN_FRAME_STATE_IDLE,
+    BEGIN_FRAME_STATE_INSIDE_BEGIN_FRAME,
+    BEGIN_FRAME_STATE_DEADLINE_PENDING,
+    BEGIN_FRAME_STATE_INSIDE_DEADLINE,
+  };
+  static const char* BeginFrameStateToString(BeginFrameState state);
+
   enum CommitState {
     COMMIT_STATE_IDLE,
     COMMIT_STATE_FRAME_IN_PROGRESS,
@@ -82,8 +94,7 @@ class CC_EXPORT SchedulerStateMachine {
       ForcedRedrawOnTimeoutState state);
 
   bool CommitPending() const {
-    return commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS ||
-           commit_state_ == COMMIT_STATE_READY_TO_COMMIT;
+    return commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS;
   }
 
   bool RedrawPending() const { return needs_redraw_; }
@@ -107,19 +118,23 @@ class CC_EXPORT SchedulerStateMachine {
 
   Action NextAction() const;
   void UpdateState(Action action);
+  void AdvanceBeginFrameStateWhenNoActionsRemain();
+
   void CheckInvariants();
 
   // Indicates whether the main thread needs a begin frame callback in order to
   // make progress.
+  bool BeginFrameNeededByImplThread() const;
   bool BeginFrameNeededToDrawByImplThread() const;
   bool ProactiveBeginFrameWantedByImplThread() const;
 
   // Indicates that the system has entered and left a BeginFrame callback.
   // The scheduler will not draw more than once in a given BeginFrame
   // callback nor send more than one BeginFrame message.
-  void DidEnterBeginFrame(const BeginFrameArgs& args);
-  void DidLeaveBeginFrame();
-  bool inside_begin_frame() const { return inside_begin_frame_; }
+  void OnBeginFrame(const BeginFrameArgs& args);
+  void OnBeginFrameDeadline();
+  bool ShouldTriggerBeginFrameDeadlineEarly() const;
+  bool InsideBeginFrame() const;
 
   // Indicates whether the LayerTreeHostImpl is visible.
   void SetVisible(bool visible);
@@ -127,13 +142,13 @@ class CC_EXPORT SchedulerStateMachine {
   // Indicates that a redraw is required, either due to the impl tree changing
   // or the screen being damaged and simply needing redisplay.
   void SetNeedsRedraw();
+  bool needs_redraw() const { return needs_redraw_; }
 
   // Indicates that a redraw is required because we are currently rendering
   // with a low resolution or checkerboarded tile.
   void DidSwapUseIncompleteTile();
 
-  // Indicates whether ACTION_DRAW_AND_SWAP_IF_POSSIBLE drew to the screen or
-  // not.
+  // Indicates whether ACTION_DRAW_AND_SWAP_IF_POSSIBLE drew to the screen.
   void DidDrawIfPossibleCompleted(bool success);
 
   // Indicates that a new commit flow needs to be performed, either to pull
@@ -202,9 +217,11 @@ class CC_EXPORT SchedulerStateMachine {
   bool ShouldCommit() const;
 
   bool HasDrawnThisFrame() const;
+  bool HasDrawnThisDrawAttempt() const;
   bool HasActivatedPendingTreeThisFrame() const;
-  bool HasUpdatedVisibleTilesThisFrame() const;
+  bool HasUpdatedVisibleTilesThisDrawAttempt() const;
   bool HasSentBeginFrameToMainThreadThisFrame() const;
+  bool HasActivatedPendingTreeThisDrawAttempt() const;
 
   void UpdateStateOnCommit(bool commit_was_aborted);
   void UpdateStateOnActivation();
@@ -213,24 +230,31 @@ class CC_EXPORT SchedulerStateMachine {
   const SchedulerSettings settings_;
 
   OutputSurfaceState output_surface_state_;
+  BeginFrameState begin_frame_state_;
   CommitState commit_state_;
   TextureState texture_state_;
   ForcedRedrawOnTimeoutState forced_redraw_state_;
   SynchronousReadbackState readback_state_;
 
+  BeginFrameArgs last_begin_frame_args_;
+
   int commit_count_;
-  int current_frame_number_;
-  int last_frame_number_where_begin_frame_sent_to_main_thread_;
-  int last_frame_number_swap_performed_;
-  int last_frame_number_where_update_visible_tiles_was_called_;
+  int begin_frame_count_;
+  int draw_attempt_count_;
+  int last_begin_frame_count_swap_performed_;
+  int last_draw_attempt_count_draw_was_called_;
+  int last_begin_frame_count_begin_frame_sent_to_main_thread_;
+  int last_draw_attempt_count_tree_activation_attempted_;
+  int last_draw_attempt_count_completed_tile_uploads_checked_;
+  int last_draw_attempt_count_update_visible_tiles_was_called_;
+
   int consecutive_failed_draws_;
   int maximum_number_of_failed_draws_before_draw_is_forced_;
+
   bool needs_redraw_;
   bool swap_used_incomplete_tile_;
   bool needs_commit_;
   bool main_thread_needs_layer_textures_;
-  bool inside_begin_frame_;
-  BeginFrameArgs last_begin_frame_args_;
   bool visible_;
   bool can_start_;
   bool can_draw_;