cc: Use multiple PrepareTiles approaches

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 <string>
 
 #include "base/basictypes.h"
@@ skipping 49 matching lines @@
     BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME,
     BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE,
   };
   static const char* BeginImplFrameStateToString(BeginImplFrameState state);
 
   enum BeginImplFrameDeadlineMode {
     BEGIN_IMPL_FRAME_DEADLINE_MODE_NONE,
     BEGIN_IMPL_FRAME_DEADLINE_MODE_IMMEDIATE,
     BEGIN_IMPL_FRAME_DEADLINE_MODE_REGULAR,
     BEGIN_IMPL_FRAME_DEADLINE_MODE_LATE,
+    BEGIN_IMPL_FRAME_DEADLINE_MODE_TRY_TO_AVOID_CHECKERBOARD,
     BEGIN_IMPL_FRAME_DEADLINE_MODE_BLOCKED_ON_READY_TO_DRAW,
   };
   static const char* BeginImplFrameDeadlineModeToString(
       BeginImplFrameDeadlineMode mode);
 
   enum CommitState {
     COMMIT_STATE_IDLE,
     COMMIT_STATE_BEGIN_MAIN_FRAME_SENT,
     COMMIT_STATE_BEGIN_MAIN_FRAME_STARTED,
     COMMIT_STATE_READY_TO_COMMIT,
     COMMIT_STATE_WAITING_FOR_ACTIVATION,
     COMMIT_STATE_WAITING_FOR_DRAW,
   };
   static const char* CommitStateToString(CommitState state);
 
-  enum ForcedRedrawOnTimeoutState {
-    FORCED_REDRAW_STATE_IDLE,
-    FORCED_REDRAW_STATE_WAITING_FOR_COMMIT,
-    FORCED_REDRAW_STATE_WAITING_FOR_ACTIVATION,
-    FORCED_REDRAW_STATE_WAITING_FOR_DRAW,
+  enum PrepareTilesApproach {
+    // PREPARE_TILES_APPROACH_PRIORITIZE_LATENCY calls PrepareTiles after
+    // every commit and after draws if there wasn't a commit for that frame.
+    // NotifyReadyToActivate and NotifyReadyToDraw are NOT trustworthy, but
+    // can be used as hints.
+    // The scheduler only calls DrawAndSwapIfPossible with this approach.
+    // We transition to PREPARE_TILES_APPROACH_ACCURATE_ACTIVE_WORK whenever
+    // DrawAndSwapIfPossible aborts due to checkerboards.
+    PREPARE_TILES_APPROACH_PRIORITIZE_LATENCY,
+    // PREPARE_TILES_APPROACH_ACCURATE_ACTIVE_WORK only calls PrepareTiles at
+    // the start of a frame so new active tree work starts ASAP, but the
+    // pending tree work doesn't.
+    // NotifyReadyToActivate and NotifyReadyToDraw are trustworthy.
+    // The scheduler only calls DrawAndSwapForced with this approach.
+    // We transition to PREPARE_TILES_APPROACH_PRIORITIZE_LATENCY upon
+    // either going idle or recovering main-thread latency.
+    PREPARE_TILES_APPROACH_ACCURATE_ACTIVE_WORK,
   };
-  static const char* ForcedRedrawOnTimeoutStateToString(
-      ForcedRedrawOnTimeoutState state);
+  static const char* PrepareTilesApproachToString(
+      PrepareTilesApproach approach);
+
+  enum PrepareTilesReason {
+    PREPARE_TILES_NOT_NEEDED,
+    PREPARE_TILES_REQUESTED,
+    PREPARE_TILES_NEEDED_FOR_COMMIT,
+    PREPARE_TILES_NEEDED_FOR_ABORTED_DRAW,
+    PREPARE_TILES_NEEDED_TO_EVICT_TILES,
+  };
+  static const char* PrepareTilesReasonToString(PrepareTilesReason reason);
 
   bool CommitPending() const {
     return commit_state_ == COMMIT_STATE_BEGIN_MAIN_FRAME_SENT ||
            commit_state_ == COMMIT_STATE_BEGIN_MAIN_FRAME_STARTED ||
            commit_state_ == COMMIT_STATE_READY_TO_COMMIT;
   }
   CommitState commit_state() const { return commit_state_; }
 
   bool RedrawPending() const { return needs_redraw_; }
-  bool PrepareTilesPending() const { return needs_prepare_tiles_; }
+  bool PrepareTilesPending() const {
+    return prepare_tiles_reason_ != PREPARE_TILES_NOT_NEEDED;
+  }
 
   enum Action {
     ACTION_NONE,
     ACTION_ANIMATE,
     ACTION_SEND_BEGIN_MAIN_FRAME,
     ACTION_COMMIT,
     ACTION_ACTIVATE_SYNC_TREE,
     ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
     ACTION_DRAW_AND_SWAP_FORCED,
     ACTION_DRAW_AND_SWAP_ABORT,
     ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
     ACTION_PREPARE_TILES,
     ACTION_INVALIDATE_OUTPUT_SURFACE,
   };
   static const char* ActionToString(Action action);
 
   scoped_refptr<base::trace_event::ConvertableToTraceFormat> AsValue() const;
   void AsValueInto(base::trace_event::TracedValue* dict) const;
 
   Action NextAction() const;
-  void UpdateState(Action action);
+  void WillAction(Action action);
+  void DidAction(Action action);
 
   // Indicates whether the impl thread needs a BeginImplFrame callback in order
   // to make progress.
   bool BeginFrameNeeded() const;
 
+  // Indicates that the Scheduler should retry the BeginImplFrame  or the
+  // deadline because the draw aborted due to checkerboards.
+  bool retry_begin_impl_frame() const { return retry_begin_impl_frame_; }
+  bool retry_begin_impl_frame_deadline() const {
+    return retry_begin_impl_frame_deadline_;
+  }
+  void ResetRetryBeginImplFrame() {
+    retry_begin_impl_frame_ = false;
+    retry_begin_impl_frame_deadline_ = false;
+  }
+
+  // This reflects the actual state of the BeginFrameSource, not just whether
+  // the SchedulerStateMachine wants BeginFrames at this instance.
+  void NotifyBeginFrameSourceActive(bool active);
+
   // 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.
   void OnBeginImplFrame();
   void OnBeginImplFrameDeadlinePending();
   // Indicates that the scheduler has entered the draw phase. The scheduler
   // will not draw more than once in a single draw phase.
   // TODO(sunnyps): Rename OnBeginImplFrameDeadline to OnDraw or similar.
   void OnBeginImplFrameDeadline();
   void OnBeginImplFrameIdle();
@@ skipping 13 matching lines @@
   // 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_; }
 
   void SetNeedsAnimate();
   bool needs_animate() const { return needs_animate_; }
 
   // Indicates that prepare-tiles is required. This guarantees another
   // PrepareTiles will occur shortly (even if no redraw is required).
-  void SetNeedsPrepareTiles();
+  void SetNeedsPrepareTiles(bool for_commit);
 
   // Make deadline wait for ReadyToDraw signal.
   void SetWaitForReadyToDraw();
 
   // Sets how many swaps can be pending to the OutputSurface.
   void SetMaxSwapsPending(int max);
 
   // If the scheduler attempted to draw and swap, this provides feedback
   // regarding whether or not the swap actually occured. We might skip the
   // swap when there is not damage, for example.
   void DidSwapBuffers();
 
   // Indicates whether a redraw is required because we are currently rendering
   // with a low resolution or checkerboarded tile.
   void SetSwapUsedIncompleteTile(bool used_incomplete_tile);
 
   // Notification from the OutputSurface that a swap has been consumed.
   void DidSwapBuffersComplete();
 
   // Indicates whether to prioritize impl thread latency (i.e., animation
   // smoothness) over new content activation.
   void SetImplLatencyTakesPriority(bool impl_latency_takes_priority);
   bool impl_latency_takes_priority() const {
     return impl_latency_takes_priority_;
   }
 
-  // Indicates whether ACTION_DRAW_AND_SWAP_IF_POSSIBLE drew to the screen.
-  void DidDrawIfPossibleCompleted(DrawResult result);
+  // Indicates whether a draw request succeeded or not.
+  void SetDrawResult(DrawResult result);
 
   // Indicates that a new commit flow needs to be performed, either to pull
   // updates from the main thread to the impl, or to push deltas from the impl
   // thread to main.
   void SetNeedsCommit();
 
   // Call this only in response to receiving an ACTION_SEND_BEGIN_MAIN_FRAME
   // from NextAction.
   // Indicates that all painting is complete.
   void NotifyReadyToCommit();
@@ skipping 16 matching lines @@
 
   // Indicates that scheduled BeginMainFrame is started.
   void NotifyBeginMainFrameStarted();
 
   // Indicates that the pending tree is ready for activation.
   void NotifyReadyToActivate();
 
   // Indicates the active tree's visible tiles are ready to be drawn.
   void NotifyReadyToDraw();
 
+  // Indicates we shouldn't draw the active tree until we won't checkerboard.
+  void SetRequiresHighResToDraw(bool required);
+
   bool has_pending_tree() const { return has_pending_tree_; }
   bool active_tree_needs_first_draw() const {
     return active_tree_needs_first_draw_;
   }
 
-  void DidPrepareTiles();
   void DidLoseOutputSurface();
   void DidCreateAndInitializeOutputSurface();
   bool HasInitializedOutputSurface() const;
 
   // True if we need to abort draws to make forward progress.
   bool PendingDrawsShouldBeAborted() const;
 
   void SetContinuousPainting(bool continuous_painting) {
     continuous_painting_ = continuous_painting;
   }
@@ skipping 30 matching lines @@
 
   bool ShouldAnimate() const;
   bool ShouldBeginOutputSurfaceCreation() const;
   bool ShouldDraw() const;
   bool ShouldActivatePendingTree() const;
   bool ShouldSendBeginMainFrame() const;
   bool ShouldCommit() const;
   bool ShouldPrepareTiles() const;
   bool ShouldInvalidateOutputSurface() const;
 
-  void UpdateStateOnAnimate();
-  void UpdateStateOnSendBeginMainFrame();
-  void UpdateStateOnCommit(bool commit_had_no_updates);
-  void UpdateStateOnActivation();
-  void UpdateStateOnDraw(bool did_request_swap);
-  void UpdateStateOnBeginOutputSurfaceCreation();
-  void UpdateStateOnPrepareTiles();
-  void UpdateStateOnInvalidateOutputSurface();
+  void WillCommit();
+
+  void WillAnimate();
+  void WillSendBeginMainFrame();
+  void DidCommit(bool commit_had_no_updates);
+  void WillActivateSyncTree();
+  void DidDraw(bool did_request_swap);
+  void WillBeginOutputSurfaceCreation();
+  void DidPrepareTiles();
+  void WillInvalidateOutputSurface();
 
   const SchedulerSettings settings_;
 
   OutputSurfaceState output_surface_state_;
   BeginImplFrameState begin_impl_frame_state_;
   CommitState commit_state_;
-  ForcedRedrawOnTimeoutState forced_redraw_state_;
+  PrepareTilesApproach prepare_tiles_approach_;
+  PrepareTilesReason prepare_tiles_reason_;
 
   // These are used for tracing only.
   int commit_count_;
   int current_frame_number_;
   int last_frame_number_animate_performed_;
   int last_frame_number_swap_performed_;
   int last_frame_number_swap_requested_;
   int last_frame_number_begin_main_frame_sent_;
   int last_frame_number_invalidate_output_surface_performed_;
 
   // These are used to ensure that an action only happens once per frame,
   // deadline, etc.
   bool animate_funnel_;
   bool request_swap_funnel_;
   bool send_begin_main_frame_funnel_;
   bool invalidate_output_surface_funnel_;
+  // TODO(brianderson): Update the comment below.
   // 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 max_pending_swaps_;
   int pending_swaps_;
   bool needs_redraw_;
+  DrawResult last_draw_result_;
+  bool retry_begin_impl_frame_;
+  bool retry_begin_impl_frame_deadline_;
   bool needs_animate_;
-  bool needs_prepare_tiles_;
   bool needs_commit_;
   bool visible_;
   bool can_start_;
   bool can_draw_;
   bool has_pending_tree_;
   bool pending_tree_is_ready_for_activation_;
+  bool requires_high_res_to_draw_;
   bool active_tree_needs_first_draw_;
+  bool active_tree_ready_to_draw_;
   bool did_create_and_initialize_first_output_surface_;
   bool impl_latency_takes_priority_;
   bool skip_next_begin_main_frame_to_reduce_latency_;
   bool skip_begin_main_frame_to_reduce_latency_;
   bool continuous_painting_;
   bool children_need_begin_frames_;
   bool defer_commits_;
   bool video_needs_begin_frames_;
   bool last_commit_had_no_updates_;
   bool wait_for_active_tree_ready_to_draw_;
   bool did_request_swap_in_last_frame_;
   bool did_perform_swap_in_last_draw_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SchedulerStateMachine);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_STATE_MACHINE_H_