Fold BeginFrameSource::SetClientReady into AddObserver

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 108 matching lines @@
   // 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;
 
   // 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;
 
-  // Tells the Source that client is ready to handle BeginFrames messages.
-  virtual void SetClientReady() = 0;
-
   // Tracing support - Recommend (but not required) to call this implementation
   // in any override.
   virtual void AsValueInto(base::trace_event::TracedValue* dict) const = 0;
 };
 
 // Simple base class which implements a BeginFrameSource.
 // Implementation classes should:
 //  - Implement the pure virtual (Set)NeedsBeginFrames methods from
 //    BeginFrameSource.
 //  - Use the CallOnBeginFrame method to call to the observer(s).
 //  - Recommended (but not required) to call BeginFrameSourceBase::AsValueInto
 //    in their own AsValueInto implementation.
 class CC_EXPORT BeginFrameSourceBase : public BeginFrameSource {
  public:
   ~BeginFrameSourceBase() override;
 
   // BeginFrameSource
   void DidFinishFrame(size_t remaining_frames) override {}
   void AddObserver(BeginFrameObserver* obs) override;
   void RemoveObserver(BeginFrameObserver* obs) override;
-  void SetClientReady() override {}
 
   // Tracing support - Recommend (but not required) to call this implementation
   // in any override.
   void AsValueInto(base::trace_event::TracedValue* dict) const override;
 
  protected:
   BeginFrameSourceBase();
 
   // These methods should be used by subclasses to make the call to the
   // observers.
@@ skipping 82 matching lines @@
 
   scoped_ptr<DelayBasedTimeSource> time_source_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SyntheticBeginFrameSource);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_BEGIN_FRAME_SOURCE_H_