Explicitly specify contents scale for SurfaceLayer.

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 <string>
 #include <vector>
 
@@ skipping 266 matching lines @@
 
   // Begins showing delegated frames from the |frame_provider|.
   void SetShowDelegatedContent(cc::DelegatedFrameProvider* frame_provider,
                                gfx::Size frame_size_in_dip);
 
   // Begins showing content from a surface with a particular id.
   void SetShowSurface(cc::SurfaceId surface_id,
                       const cc::SurfaceLayer::SatisfyCallback& satisfy_callback,
                       const cc::SurfaceLayer::RequireCallback& require_callback,
                       gfx::Size surface_size,
+                      float scale,
                       gfx::Size frame_size_in_dip);
 
   bool has_external_content() {
     return texture_layer_.get() || delegated_renderer_layer_.get() ||
            surface_layer_.get();
   }
 
   // Show a solid color instead of delegated or surface contents.
   void SetShowSolidColorContent();
 
@@ skipping 219 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_