cc: Add more info to the BeginMainFrame dump.

cc/scheduler/begin_frame_source.h

 // Copyright 2014 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_BEGIN_FRAME_SOURCE_H_
 #define CC_SCHEDULER_BEGIN_FRAME_SOURCE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 56 matching lines @@
 // required LastUsedBeginFrameArgs behaviour.
 //
 // Users of this class should;
 //  - Implement the OnBeginFrameDerivedImpl function.
 //  - Recommended (but not required) to call
 //    BeginFrameObserverBase::OnValueInto in their overridden OnValueInto
 //    function.
 class CC_EXPORT BeginFrameObserverBase : public BeginFrameObserver {
  public:
   BeginFrameObserverBase();
+  ~BeginFrameObserverBase() override;
 
   // BeginFrameObserver
 
   // Traces |args| and DCHECK |args| satisfies pre-conditions then calls
   // OnBeginFrameDerivedImpl and updates the last_begin_frame_args_ value on
   // true.
   void OnBeginFrame(const BeginFrameArgs& args) override;
   const BeginFrameArgs& LastUsedBeginFrameArgs() const override;
 
  protected:
-  // Subclasses should override this method!
   // Return true if the given argument is (or will be) used.
   virtual bool OnBeginFrameDerivedImpl(const BeginFrameArgs& args) = 0;
 
+  void AsValueInto(base::trace_event::TracedValue* state) const;
+
   BeginFrameArgs last_begin_frame_args_;
-  int64_t dropped_begin_frame_args_;
+  int64_t dropped_begin_frame_args_ = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BeginFrameObserverBase);
 };
 
 // Interface for a class which produces BeginFrame calls to a
 // BeginFrameObserver.
 //
 // BeginFrame calls *normally* occur just after a vsync interrupt when input
 // processing has been finished and provide information about the time values
 // of the vsync times. *However*, these values can be heavily modified or even
 // plain made up (when no vsync signal is available or vsync throttling is
 // turned off). See the BeginFrameObserver for information about the guarantees
 // all BeginFrameSources *must* provide.
 class CC_EXPORT BeginFrameSource {
  public:
   BeginFrameSource();
-  virtual ~BeginFrameSource() {}
+  virtual ~BeginFrameSource();
+
+  // Returns an identifier for this BeginFrameSource. Guaranteed unique within a
+  // process, but not across processes. This is used to create BeginFrames that
+  // originate at this source. Note that BeginFrameSources may pass on
+  // BeginFrames created by other sources, with different IDs.
+  uint32_t source_id() const { return source_id_; }
 
   // BeginFrameObservers use DidFinishFrame to acknowledge that they have
   // completed handling a BeginFrame.
   //
   // The DisplayScheduler uses these acknowledgments to trigger an early
   // deadline once all BeginFrameObservers have completed a frame.
   //
   // They also provide back pressure to a frame source about frame processing
   // (rather than toggling SetNeedsBeginFrames every frame). For example, the
   // BackToBackFrameSource uses them to make sure only one frame is pending at a
@@ skipping 10 matching lines @@
 
   // Add/Remove an observer from the source. When no observers are added the BFS
   // should shut down its timers, disable vsync, etc.
   virtual void AddObserver(BeginFrameObserver* obs) = 0;
   virtual void RemoveObserver(BeginFrameObserver* obs) = 0;
 
   // Returns false if the begin frame source will just continue to produce
   // begin frames without waiting.
   virtual bool IsThrottled() const = 0;
 
-  // Returns an identifier for this BeginFrameSource. Guaranteed unique within a
-  // process, but not across processes. This is used to create BeginFrames that
-  // originate at this source. Note that BeginFrameSources may pass on
-  // BeginFrames created by other sources, with different IDs.
-  uint32_t source_id() const;
+  virtual void AsValueInto(base::trace_event::TracedValue* state) const;
 
  private:
   uint32_t source_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(BeginFrameSource);
 };
 
 // A BeginFrameSource that does nothing.
 class CC_EXPORT StubBeginFrameSource : public BeginFrameSource {
  public:
   void DidFinishFrame(BeginFrameObserver* obs,
                       const BeginFrameAck& ack) override {}
   void AddObserver(BeginFrameObserver* obs) override {}
   void RemoveObserver(BeginFrameObserver* obs) override {}
   bool IsThrottled() const override;
@@ skipping 80 matching lines @@
   uint64_t next_sequence_number_;
 
   DISALLOW_COPY_AND_ASSIGN(DelayBasedBeginFrameSource);
 };
 
 // Helper class that tracks outstanding acknowledgments from
 // BeginFrameObservers.
 class CC_EXPORT BeginFrameObserverAckTracker {
  public:
   BeginFrameObserverAckTracker();
-  virtual ~BeginFrameObserverAckTracker();
+  ~BeginFrameObserverAckTracker();
 
   // The BeginFrameSource uses these methods to notify us when a BeginFrame was
   // started, an observer finished a frame, or an observer was added/removed.
   void OnBeginFrame(const BeginFrameArgs& args);
   void OnObserverFinishedFrame(BeginFrameObserver* obs,
                                const BeginFrameAck& ack);
   void OnObserverAdded(BeginFrameObserver* obs);
   void OnObserverRemoved(BeginFrameObserver* obs);
 
   // Returns |true| if all the source's observers completed the current frame.
   bool AllObserversFinishedFrame() const;
 
   // Returns |true| if any observer had damage during the current frame.
   bool AnyObserversHadDamage() const;
 
   // Return the sequence number of the latest frame that all active observers
   // have confirmed.
   uint64_t LatestConfirmedSequenceNumber() const;
 
+  void AsValueInto(base::trace_event::TracedValue* state) const;
+
  private:
   void SourceChanged(const BeginFrameArgs& args);
 
-  uint32_t current_source_id_;
-  uint64_t current_sequence_number_;
+  uint32_t current_source_id_ = 0;
+  uint64_t current_sequence_number_ = BeginFrameArgs::kStartingFrameNumber;
   // Small sets, but order matters for intersection computation.
   base::flat_set<BeginFrameObserver*> observers_;
   base::flat_set<BeginFrameObserver*> finished_observers_;
-  bool observers_had_damage_;
+  bool observers_had_damage_ = false;
   base::SmallMap<std::map<BeginFrameObserver*, uint64_t>, 4>
       latest_confirmed_sequence_numbers_;
+
+  DISALLOW_COPY_AND_ASSIGN(BeginFrameObserverAckTracker);
 };
 
 class CC_EXPORT ExternalBeginFrameSourceClient {
  public:
   // Only called when changed.  Assumed false by default.
   virtual void OnNeedsBeginFrames(bool needs_begin_frames) = 0;
   // Called when all observers have completed a frame.
   virtual void OnDidFinishFrame(const BeginFrameAck& ack) = 0;
 };
 
 // A BeginFrameSource that is only ticked manually.  Usually the endpoint
 // of messages from some other thread/process that send OnBeginFrame and
 // receive SetNeedsBeginFrame messages.  This turns such messages back into
 // an observable BeginFrameSource.
 class CC_EXPORT ExternalBeginFrameSource : public BeginFrameSource {
  public:
   // Client lifetime must be preserved by owner past the lifetime of this class.
   explicit ExternalBeginFrameSource(ExternalBeginFrameSourceClient* client);
   ~ExternalBeginFrameSource() override;
 
   // BeginFrameSource implementation.
   void AddObserver(BeginFrameObserver* obs) override;
   void RemoveObserver(BeginFrameObserver* obs) override;
   void DidFinishFrame(BeginFrameObserver* obs,
                       const BeginFrameAck& ack) override;
   bool IsThrottled() const override;
+  void AsValueInto(base::trace_event::TracedValue* state) const override;
 
   void OnSetBeginFrameSourcePaused(bool paused);
   void OnBeginFrame(const BeginFrameArgs& args);
 
  protected:
   void MaybeFinishFrame();
   void FinishFrame();
 
-  BeginFrameArgs missed_begin_frame_args_;
+  BeginFrameArgs last_begin_frame_args_;
   std::unordered_set<BeginFrameObserver*> observers_;
   ExternalBeginFrameSourceClient* client_;
   bool paused_ = false;
   bool frame_active_ = false;
   BeginFrameObserverAckTracker ack_tracker_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ExternalBeginFrameSource);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_BEGIN_FRAME_SOURCE_H_