Add Set Authoritative VSync Interval function

cc/trees/layer_tree_host.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_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <limits>
 #include <list>
 #include <set>
@@ skipping 305 matching lines @@
   // See swap_promise.h for how to use SwapPromise.
   void QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise);
 
   void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);
 
   size_t num_queued_swap_promises() const { return swap_promise_list_.size(); }
 
   void set_surface_id_namespace(uint32_t id_namespace);
   SurfaceSequence CreateSurfaceSequence();
 
+  void SetAuthoritativeVSyncInterval(base::TimeDelta interval) const;
   void SetChildrenNeedBeginFrames(bool children_need_begin_frames) const;
   void SendBeginFramesToChildren(const BeginFrameArgs& args) const;
 
  protected:
   LayerTreeHost(LayerTreeHostClient* client,
                 SharedBitmapManager* shared_bitmap_manager,
                 gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
                 const LayerTreeSettings& settings);
   void InitializeThreaded(
       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
@@ skipping 147 matching lines @@
 
   uint32_t surface_id_namespace_;
   uint32_t next_surface_sequence_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_