[cc] Calculate the correct latest_confirmed_sequence_number in cc::Scheduler.

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>
 #include <string>
 
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
-#include "cc/output/begin_frame_args.h"
 #include "cc/scheduler/commit_earlyout_reason.h"
 #include "cc/scheduler/draw_result.h"
 #include "cc/scheduler/scheduler_settings.h"
 #include "cc/tiles/tile_priority.h"
 
 namespace base {
 namespace trace_event {
 class ConvertableToTraceFormat;
 class TracedValue;
 }
@@ skipping 115 matching lines @@
   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 Scheduler has received a BeginFrame that did not require
+  // a BeginImplFrame, because the Scheduler stopped observing BeginFrames.
+  // Updates the sequence and freshness numbers for the dropped BeginFrame.
+  void OnBeginFrameDroppedNotObserving(uint32_t source_id,
+                                       uint64_t sequence_number);
+
   // 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 OnBeginImplFrame(uint32_t source_id, uint64_t sequence_number);
   // 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();
 
   int current_frame_number() const { return current_frame_number_; }
 
   BeginImplFrameState begin_impl_frame_state() const {
     return begin_impl_frame_state_;
@@ skipping 112 matching lines @@
 
   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_;
   }
 
+  uint32_t begin_frame_source_id() const { return begin_frame_source_id_; }
+  uint64_t last_begin_frame_sequence_number_compositor_frame_was_fresh() const {
+    return last_begin_frame_sequence_number_compositor_frame_was_fresh_;
+  }
+
  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);
 
+  void UpdateBeginFrameSequenceNumbersForBeginFrame(uint32_t source_id,
+                                                    uint64_t sequence_number);
+  void UpdateBeginFrameSequenceNumbersForBeginFrameDeadline();
+
   const SchedulerSettings settings_;
 
   CompositorFrameSinkState compositor_frame_sink_state_;
   BeginImplFrameState begin_impl_frame_state_;
   BeginMainFrameState begin_main_frame_state_;
   ForcedRedrawOnTimeoutState forced_redraw_state_;
 
+  // These fields are used to track the freshness of pending updates in the
+  // commit/activate/draw pipeline. The Scheduler uses the CompositorFrame's
+  // freshness to fill the |latest_confirmed_sequence_number| field in
+  // BeginFrameAcks.
+  uint32_t begin_frame_source_id_;
+  uint64_t begin_frame_sequence_number_;
+  uint64_t last_begin_frame_sequence_number_begin_main_frame_sent_;
+  uint64_t last_begin_frame_sequence_number_pending_tree_was_fresh_;
+  uint64_t last_begin_frame_sequence_number_active_tree_was_fresh_;
+  uint64_t last_begin_frame_sequence_number_compositor_frame_was_fresh_;
+
   // 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.
@@ skipping 38 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_