Enable BeginFrame scheduling on aura

ui/compositor/compositor.h

 // Copyright (c) 2012 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 UI_COMPOSITOR_COMPOSITOR_H_
 #define UI_COMPOSITOR_COMPOSITOR_H_
 
 #include <list>
 #include <string>
 
@@ skipping 202 matching lines @@
   // Sets the background color used for areas that aren't covered by
   // the |root_layer|.
   void SetBackgroundColor(SkColor color);
 
   // Sets the visibility of the underlying compositor.
   void SetVisible(bool visible);
 
   // Gets the visibility of the underlying compositor.
   bool IsVisible();
 
+  // The "authoritative" vsync interval, if provided, will override interval
+  // reported from 3D context. This is typically the value reported by a more
+  // reliable source, e.g, the platform display configuration.
+  // In the particular case of ChromeOS -- this is the value queried through
+  // XRandR, which is more reliable than the value queried through the 3D
+  // context.
+  void SetAuthoritativeVSyncInterval(const base::TimeDelta& interval);
+
   // Returns the widget for this compositor.
   gfx::AcceleratedWidget widget() const { return widget_; }
 
   // Returns the vsync manager for this compositor.
   scoped_refptr<CompositorVSyncManager> vsync_manager() const;
 
   // Returns the main thread task runner this compositor uses. Users of the
   // compositor generally shouldn't use this.
   scoped_refptr<base::SingleThreadTaskRunner> task_runner() const {
     return task_runner_;
@@ skipping 123 matching lines @@
   cc::BeginFrameArgs missed_begin_frame_args_;
 
   base::WeakPtrFactory<Compositor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_COMPOSITOR_H_