Aura-Mus: Implement gutter in the embedder.

ui/aura/mus/window_port_mus.h

 // Copyright 2016 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_AURA_MUS_WINDOW_PORT_MUS_H_
 #define UI_AURA_MUS_WINDOW_PORT_MUS_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 36 matching lines @@
 
   static WindowPortMus* Get(Window* window);
 
   Window* window() { return window_; }
   const Window* window() const { return window_; }
 
   ClientSurfaceEmbedder* client_surface_embedder() const {
     return client_surface_embedder_.get();
   }
 
+  const cc::SurfaceInfo& PrimarySurfaceInfoForTesting() const {
+    return primary_surface_info_;
+  }
+
   void SetTextInputState(mojo::TextInputStatePtr state);
   void SetImeVisibility(bool visible, mojo::TextInputStatePtr state);
 
   ui::mojom::CursorType predefined_cursor() const { return predefined_cursor_; }
   void SetPredefinedCursor(ui::mojom::CursorType cursor_id);
 
   // Sets the EventTargetingPolicy, default is TARGET_AND_DESCENDANTS.
   void SetEventTargetingPolicy(ui::mojom::EventTargetingPolicy policy);
 
   // Sets whether this window can accept drops, defaults to false.
@@ skipping 202 matching lines @@
   // Used when this window is embedding a client.
   std::unique_ptr<ClientSurfaceEmbedder> client_surface_embedder_;
 
   ServerChangeIdType next_server_change_id_ = 0;
   ServerChanges server_changes_;
 
   cc::FrameSinkId frame_sink_id_;
   base::Closure pending_compositor_frame_sink_request_;
 
   cc::SurfaceInfo primary_surface_info_;
+  cc::SurfaceInfo fallback_surface_info_;
 
   cc::LocalSurfaceId local_surface_id_;
   cc::LocalSurfaceIdAllocator local_surface_id_allocator_;
   gfx::Size last_surface_size_;
 
   ui::mojom::CursorType predefined_cursor_ = ui::mojom::CursorType::CURSOR_NULL;
 
   DISALLOW_COPY_AND_ASSIGN(WindowPortMus);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_MUS_WINDOW_PORT_MUS_H_