cc: Emulate BeginFrame in OutputSurfaces that don't support it natively

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 <string>
 
 #include "base/basictypes.h"
@@ skipping 61 matching lines @@
 
   // Indicates whether the main thread needs a begin frame callback in order to
   // make progress.
   bool BeginFrameNeededByImplThread() const;
 
   // Indicates that the system has entered and left a BeginFrame callback.
   // The scheduler will not draw more than once in a given BeginFrame
   // callback.
   void DidEnterBeginFrame();
   void DidLeaveBeginFrame();
+  bool inside_begin_frame() const { return inside_begin_frame_; }
 
   // Indicates whether the LayerTreeHostImpl is visible.
   void SetVisible(bool visible);
 
   // Indicates that a redraw is required, either due to the impl tree changing
   // or the screen being damaged and simply needing redisplay.
   void SetNeedsRedraw();
 
   // As SetNeedsRedraw(), but ensures the draw will definitely happen even if
   // we are not visible.
@@ skipping 100 matching lines @@
   TextureState texture_state_;
   OutputSurfaceState output_surface_state_;
   bool did_create_and_initialize_first_output_surface_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerStateMachine);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_STATE_MACHINE_H_