cc: Add scheduler support for invalidating content on impl thread.

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 <memory>
 #include <string>
 
@@ skipping 97 matching lines @@
   }
 
   bool RedrawPending() const { return needs_redraw_; }
   bool PrepareTilesPending() const { return needs_prepare_tiles_; }
 
   enum Action {
     ACTION_NONE,
     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,
   };
   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 WillCommit(bool commit_had_no_updates);
   void WillActivate();
   void WillDraw();
   void WillBeginCompositorFrameSinkCreation();
   void WillPrepareTiles();
   void WillInvalidateCompositorFrameSink();
+  void WillPerformImplSideInvalidation();
 
   void DidDraw(DrawResult draw_result);
 
   void AbortDraw();
 
   // Indicates whether the impl thread needs a BeginImplFrame callback in order
   // to make progress.
   bool BeginFrameNeeded() const;
 
   // Indicates that the system has entered and left a BeginImplFrame callback.
@@ skipping 94 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();
 
+  void SetNeedsImplSideInvalidation();
+
   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 DidLoseCompositorFrameSink();
   void DidCreateAndInitializeCompositorFrameSink();
   bool HasInitializedCompositorFrameSink() const;
 
   // True if we need to abort draws to make forward progress.
   bool PendingDrawsShouldBeAborted() const;
 
   bool CouldSendBeginMainFrame() const;
 
   void SetDeferCommits(bool defer_commits);
 
   void SetVideoNeedsBeginFrames(bool video_needs_begin_frames);
   bool video_needs_begin_frames() const { return video_needs_begin_frames_; }
 
   bool did_submit_in_last_frame() const { return did_submit_in_last_frame_; }
 
+  bool needs_impl_side_invalidation() const {
+    return needs_impl_side_invalidation_;
+  }
+  bool previous_pending_tree_was_impl_side() const {
+    return previous_pending_tree_was_impl_side_;
+  }
+
  protected:
   bool BeginFrameRequiredForAction() const;
   bool BeginFrameNeededForVideo() const;
   bool ProactiveBeginFrameWanted() const;
 
+  bool ShouldPerformImplSideInvalidation() const;
+  bool CouldCreatePendingTree() const;
+
   bool ShouldTriggerBeginImplFrameDeadlineImmediately() const;
 
   // True if we need to force activations to make forward progress.
   // 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;
 
   void WillDrawInternal();
+  void WillPerformImplSideInvalidationInternal();
   void DidDrawInternal(DrawResult draw_result);
 
   const SchedulerSettings settings_;
 
   CompositorFrameSinkState compositor_frame_sink_state_;
   BeginImplFrameState begin_impl_frame_state_;
   BeginMainFrameState begin_main_frame_state_;
   ForcedRedrawOnTimeoutState forced_redraw_state_;
 
   // These are used for tracing only.
   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 invalidate_compositor_frame_sink_funnel_;
+  bool impl_side_invalidation_funnel_;
   // 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 12 matching lines @@
   ScrollHandlerState scroll_handler_state_;
   bool critical_begin_main_frame_to_activate_is_fast_;
   bool main_thread_missed_last_deadline_;
   bool skip_next_begin_main_frame_to_reduce_latency_;
   bool defer_commits_;
   bool video_needs_begin_frames_;
   bool last_commit_had_no_updates_;
   bool wait_for_ready_to_draw_;
   bool did_draw_in_last_frame_;
   bool did_submit_in_last_frame_;
+  bool needs_impl_side_invalidation_;
+
+  bool previous_pending_tree_was_impl_side_;

[Khushal, 2017/02/22 18:56:41]

Added this after I ran into a DCHECK when trying this out on a page. The
SchedulerTest should also catch this now.

+  bool current_pending_tree_is_impl_side_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SchedulerStateMachine);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_STATE_MACHINE_H_