cc: Use BeginFrameArgs

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 5c7d5b5b8a773ede49feecaa082991d0446155d0..eb59f282f49ff1c7ec44312be69a0f7bb4b06f3e 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -31,12 +31,31 @@ class CC_EXPORT SchedulerStateMachine {
   // settings must be valid for the lifetime of this class.
   explicit SchedulerStateMachine(const SchedulerSettings& settings);
 
+  enum OutputSurfaceState {
+    OUTPUT_SURFACE_ACTIVE,
+    OUTPUT_SURFACE_LOST,
+    OUTPUT_SURFACE_CREATING,
+    OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT,
+    OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION,
+  };
+
+  // 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,
+  };
+
   enum CommitState {
     COMMIT_STATE_IDLE,
     COMMIT_STATE_FRAME_IN_PROGRESS,
     COMMIT_STATE_READY_TO_COMMIT,
+    COMMIT_STATE_WAITING_FOR_ACTIVATION,
     COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
-    COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW,
   };
 
   enum TextureState {
@@ -45,15 +64,25 @@ class CC_EXPORT SchedulerStateMachine {
     LAYER_TEXTURE_STATE_ACQUIRED_BY_IMPL_THREAD,
   };
 
-  enum OutputSurfaceState {
-    OUTPUT_SURFACE_ACTIVE,
-    OUTPUT_SURFACE_LOST,
-    OUTPUT_SURFACE_CREATING,
+  enum SynchronousReadbackState {
+    READBACK_STATE_IDLE,
+    READBACK_STATE_FORCED_COMMIT_REQUESTED,
+    READBACK_STATE_FORCED_COMMIT_PENDING,
+    READBACK_STATE_WAITING_FOR_ACTIVATION,
+    READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK,
+    READBACK_STATE_REPLACEMENT_COMMIT_PENDING,
+    READBACK_STATE_REPLACEMENT_COMMIT_ACTIVATING,
+  };
+
+  enum ForcedRedrawOnTimeoutState {
+    FORCED_REDRAW_STATE_IDLE,
+    FORCED_REDRAW_STATE_WAITING_FOR_COMMIT,
+    FORCED_REDRAW_STATE_WAITING_FOR_ACTIVATION,
+    FORCED_REDRAW_STATE_WAITING_FOR_DRAW,
   };
 
   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_; }
@@ -63,26 +92,31 @@ class CC_EXPORT SchedulerStateMachine {
     ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
     ACTION_COMMIT,
     ACTION_UPDATE_VISIBLE_TILES,
-    ACTION_ACTIVATE_PENDING_TREE_IF_NEEDED,
-    ACTION_DRAW_IF_POSSIBLE,
-    ACTION_DRAW_FORCED,
+    ACTION_ACTIVATE_PENDING_TREE,
+    ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
+    ACTION_DRAW_AND_SWAP_FORCED,
+    ACTION_DRAW_AND_SWAP_ABORT,
+    ACTION_DRAW_AND_READBACK,
     ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
     ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD,
   };
   Action NextAction() const;
   void UpdateState(Action action);
+  void AdvanceBeginFrameStateWhenNoActionsRemain();
 
   // Indicates whether the main thread needs a begin frame callback in order to
   // make progress.
+  bool BeginFrameNeededByImplThread() const;
   bool BeginFrameNeededToDrawByImplThread() const;
-  bool ProactiveBeginFrameWantedByImplThread() const;
+  bool BeginFrameProactivelyNeededByImplThread() 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);
@@ -90,16 +124,13 @@ 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();
-
-  // As SetNeedsRedraw(), but ensures the draw will definitely happen even if
-  // we are not visible.
-  void SetNeedsForcedRedraw();
+  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_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
@@ -111,7 +142,7 @@ class CC_EXPORT SchedulerStateMachine {
   // thread even if we are not visible.  After this call we expect to go through
   // the forced commit flow and then return to waiting for a non-forced
   // begin frame to finish.
-  void SetNeedsForcedCommit();
+  void SetNeedsForcedCommitForReadback();
 
   // Call this only in response to receiving an
   // ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD from NextAction.
@@ -126,8 +157,8 @@ class CC_EXPORT SchedulerStateMachine {
 
   // Request exclusive access to the textures that back single buffered
   // layers on behalf of the main thread. Upon acquisition,
-  // ACTION_DRAW_IF_POSSIBLE will not draw until the main thread releases the
-  // textures to the impl thread by committing the layers.
+  // ACTION_DRAW_AND_SWAP_IF_POSSIBLE will not draw until the main thread
+  // releases the textures to the impl thread by committing the layers.
   void SetMainThreadNeedsLayerTextures();
 
   // Set that we can create the first OutputSurface and start the scheduler.
@@ -136,14 +167,18 @@ class CC_EXPORT SchedulerStateMachine {
   // Indicates whether drawing would, at this time, make sense.
   // CanDraw can be used to supress flashes or checkerboarding
   // when such behavior would be undesirable.
-  void SetCanDraw(bool can);
+  void SetCanDraw(bool can_draw);
 
-  // Indicates whether or not there is a pending tree.  This influences
-  // whether or not we can succesfully commit at this time.  If the
+  // Indicates that the pending tree is ready for activation.
+  void NotifyReadyToActivate();
+
+  // Indicates whether or not there is a pending tree (which may be null)
+  // and whether the active tree is null or not.  This
+  // influences whether or not we can succesfully commit at this time.  If the
   // last commit is still being processed (but not blocking), it may not
   // be possible to take another commit yet.  This overrides force commit,
   // as a commit is already still in flight.
-  void SetHasPendingTree(bool has_pending_tree);
+  void SetHasTrees(bool has_pending_tree, bool active_tree_is_null);
   bool has_pending_tree() const { return has_pending_tree_; }
 
   void DidLoseOutputSurface();
@@ -163,44 +198,56 @@ class CC_EXPORT SchedulerStateMachine {
   bool ShouldDrawForced() const;
   bool ScheduledToDraw() const;
   bool ShouldDraw() const;
-  bool ShouldAttemptTreeActivation() const;
+  bool ShouldDrawInternal(BeginFrameState begin_frame_state) const;
+  bool ShouldActivatePendingTree() const;
   bool ShouldAcquireLayerTexturesForMainThread() const;
   bool ShouldUpdateVisibleTiles() const;
+  bool ShouldSendBeginFrameToMainThread() const;
   bool HasDrawnThisFrame() const;
-  bool HasAttemptedTreeActivationThisFrame() const;
-  bool HasUpdatedVisibleTilesThisFrame() const;
-  void SetPostCommitFlags();
+  bool HasDrawnThisDrawAttempt() const;
+  bool HasUpdatedVisibleTilesThisDrawAttempt() const;
+  bool HasSentBeginFrameToMainThreadThisFrame() const;
+  bool HasActivatedPendingTreeThisDrawAttempt() const;
+
+  void HandleCommitInternal(bool commit_was_aborted);
+  void UpdateStateOnDraw(bool did_swap);
 
   const SchedulerSettings settings_;
 
+  OutputSurfaceState output_surface_state_;
+  BeginFrameState begin_frame_state_;
   CommitState commit_state_;
+  TextureState texture_state_;
+  SynchronousReadbackState readback_state_;
+  ForcedRedrawOnTimeoutState forced_redraw_state_;
+
+  BeginFrameArgs last_begin_frame_args_;
+
   int commit_count_;
+  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 current_frame_number_;
-  int last_frame_number_where_begin_frame_sent_to_main_thread_;
-  int last_frame_number_where_draw_was_called_;
-  int last_frame_number_where_tree_activation_attempted_;
-  int last_frame_number_where_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_forced_redraw_;
-  bool needs_forced_redraw_after_next_commit_;
-  bool needs_redraw_after_next_commit_;
   bool needs_commit_;
-  bool needs_forced_commit_;
-  bool expect_immediate_begin_frame_for_main_thread_;
   bool main_thread_needs_layer_textures_;
-  bool inside_begin_frame_;
-  BeginFrameArgs last_begin_frame_args_;
+  bool active_tree_has_been_drawn_;
+  bool active_tree_is_null_;
   bool visible_;
   bool can_start_;
   bool can_draw_;
   bool has_pending_tree_;
+  bool pending_tree_is_ready_for_activation_;
   bool draw_if_possible_failed_;
-  TextureState texture_state_;
-  OutputSurfaceState output_surface_state_;
   bool did_create_and_initialize_first_output_surface_;
 
  private: