exo: Add support for subcompositor interface.

components/exo/shell_surface.h

 // Copyright 2015 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 COMPONENTS_EXO_SHELL_SURFACE_H_
 #define COMPONENTS_EXO_SHELL_SURFACE_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
 #include "components/exo/surface_delegate.h"
+#include "components/exo/surface_observer.h"
 #include "ui/views/widget/widget_delegate.h"
 
 namespace base {
 namespace trace_event {
 class TracedValue;
 }
 }
 
 namespace exo {
 class Surface;
 
 // This class provides functions for treating a surfaces like toplevel,
 // fullscreen or popup widgets, move, resize or maximize them, associate
 // metadata like title and class, etc.
-class ShellSurface : public SurfaceDelegate, public views::WidgetDelegate {
+class ShellSurface : public SurfaceDelegate,
+                     public SurfaceObserver,
+                     public views::WidgetDelegate {
  public:
   explicit ShellSurface(Surface* surface);
   ~ShellSurface() override;
 
   // Show surface at the time of the next commit.
   void Show();
 
   // Show surface as a toplevel window with decorations.
   void SetToplevel();
 
   // Make the surface fullscreen.
   void SetFullscreen(bool fullscreen);
 
   // Set title for surface.
   void SetTitle(const base::string16& title);
 
   // Returns a trace value representing the state of the surface.
   scoped_refptr<base::trace_event::TracedValue> AsTracedValue() const;
 
   // Overridden from SurfaceDelegate:
-  void OnSurfaceDestroying() override;
   void OnSurfaceCommit() override;
+  bool IsSurfaceSynchronized() const override;
+
+  // Overridden from SurfaceObserver:
+  void OnSurfaceDestroying(Surface* surface) override;
 
   // Overridden from views::WidgetDelegate:
   base::string16 GetWindowTitle() const override;
   views::Widget* GetWidget() override;
   const views::Widget* GetWidget() const override;
   views::View* GetContentsView() override;
   views::NonClientFrameView* CreateNonClientFrameView(
       views::Widget* widget) override;
 
  private:
   scoped_ptr<views::Widget> widget_;
   Surface* surface_;
   ui::WindowShowState show_state_;
   base::string16 title_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellSurface);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_SHELL_SURFACE_H_