cc: Remove retro frames from scheduler.

cc/scheduler/begin_frame_source.h

Index: cc/scheduler/begin_frame_source.h
diff --git a/cc/scheduler/begin_frame_source.h b/cc/scheduler/begin_frame_source.h
index cc238deb616928183134b0f9f2bc2f16f872c880..f33d98d83512dcbf2d7b4d12788d961dc9cc66f5 100644
--- a/cc/scheduler/begin_frame_source.h
+++ b/cc/scheduler/begin_frame_source.h
@@ -66,42 +66,6 @@ class CC_EXPORT BeginFrameObserver {
   virtual void AsValueInto(base::trace_event::TracedValue* dict) const = 0;
 };
 
-// Simple base class which implements a BeginFrameObserver which checks the
-// incoming values meet the BeginFrameObserver requirements and implements the
-// 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 {

[enne (OOO), 2016/04/14 23:02:26]

Hmm, this was useful because it implemented some functions like
LastUsedBeginFrameArgs and AsValueInto automatically.  I was going to use these
in https://codereview.chromium.org/1841083007/.  Maybe it should just be wrapped
into the base class or there's some other cleanup that makes sense.  What do you
think?

- public:
-  BeginFrameObserverBase();
-
-  // 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;
-
-  // Outputs last_begin_frame_args_
-  void AsValueInto(base::trace_event::TracedValue* dict) 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;
-
-  BeginFrameArgs last_begin_frame_args_;
-  int64_t dropped_begin_frame_args_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(BeginFrameObserverBase);
-};
-
 // Interface for a class which produces BeginFrame calls to a
 // BeginFrameObserver.
 //
@@ -119,7 +83,7 @@ class CC_EXPORT BeginFrameSource {
   // processing (rather than toggling SetNeedsBeginFrames every frame). It is
   // used by systems like the BackToBackFrameSource to make sure only one frame
   // is pending at a time.
-  virtual void DidFinishFrame(size_t remaining_frames) = 0;
+  virtual void DidFinishFrame(BeginFrameObserver* obs) = 0;
 
   // Add/Remove an observer from the source. When no observers are added the BFS
   // should shut down its timers, disable vsync, etc.
@@ -143,7 +107,7 @@ class CC_EXPORT BeginFrameSourceBase : public BeginFrameSource {
   ~BeginFrameSourceBase() override;
 
   // BeginFrameSource
-  void DidFinishFrame(size_t remaining_frames) override {}
+  void DidFinishFrame(BeginFrameObserver* obs) override {}
   void AddObserver(BeginFrameObserver* obs) override;
   void RemoveObserver(BeginFrameObserver* obs) override;
 
@@ -182,10 +146,8 @@ class CC_EXPORT BackToBackBeginFrameSource : public BeginFrameSourceBase {
       base::SingleThreadTaskRunner* task_runner);
   ~BackToBackBeginFrameSource() override;
 
-  // BeginFrameSource
-  void DidFinishFrame(size_t remaining_frames) override;
-
   // BeginFrameSourceBase
+  void DidFinishFrame(BeginFrameObserver* obs) override;
   void AddObserver(BeginFrameObserver* obs) override;
   void OnNeedsBeginFramesChanged(bool needs_begin_frames) override;
 
@@ -222,6 +184,7 @@ class CC_EXPORT SyntheticBeginFrameSource : public BeginFrameSourceBase,
                                base::TimeDelta new_vsync_interval);
 
   // BeginFrameSourceBase
+  void DidFinishFrame(BeginFrameObserver* obs) override;
   void AddObserver(BeginFrameObserver* obs) override;
   void OnNeedsBeginFramesChanged(bool needs_begin_frames) override;