Aura-Mus: Enable Surface Synchronization behind flag

ui/compositor/layer.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_LAYER_H_
 #define UI_COMPOSITOR_LAYER_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 281 matching lines @@
       gfx::Size texture_size_in_dip);
   void SetTextureSize(gfx::Size texture_size_in_dip);
   void SetTextureFlipped(bool flipped);
   bool TextureFlipped() const;
 
   // Begins showing content from a surface with a particular ID.
   void SetShowPrimarySurface(
       const cc::SurfaceInfo& surface_info,
       scoped_refptr<cc::SurfaceReferenceFactory> surface_ref);
 
+  // In the event that the primary surface is not yet available in the
+  // display compositor, the fallback surface will be used.
+  void SetFallbackSurface(
+      const cc::SurfaceInfo& surface_info,
+      scoped_refptr<cc::SurfaceReferenceFactory> surface_ref);
+
   bool has_external_content() {
     return texture_layer_.get() || surface_layer_.get();
   }
 
   // Show a solid color instead of delegated or surface contents.
   void SetShowSolidColorContent();
 
   // Sets the layer's fill color.  May only be called for LAYER_SOLID_COLOR.
   void SetColor(SkColor color);
   SkColor GetTargetColor() const;
@@ skipping 234 matching lines @@
   // The size of the frame or texture in DIP, set when SetShowDelegatedContent
   // or SetTextureMailbox was called.
   gfx::Size frame_size_in_dip_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_H_