mus: Fix showing guest views in --mash and --mus.

ui/aura/window_delegate.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_AURA_WINDOW_DELEGATE_H_
 #define UI_AURA_WINDOW_DELEGATE_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "ui/aura/aura_export.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/native_widget_types.h"
 
+namespace cc {
+class SurfaceInfo;
+}
+
 namespace gfx {
 class Path;
 class Point;
 class Rect;
 class Size;
 }
 
 namespace ui {
 class PaintContext;
 }
@@ skipping 62 matching lines @@
   // Called from Window::HitTest to check if the window has a custom hit test
   // mask. It works similar to the views counterparts. That is, if the function
   // returns true, GetHitTestMask below will be called to get the mask.
   // Otherwise, Window will hit-test against its bounds.
   virtual bool HasHitTestMask() const = 0;
 
   // Called from Window::HitTest to retrieve hit test mask when HasHitTestMask
   // above returns true.
   virtual void GetHitTestMask(gfx::Path* mask) const = 0;
 
+  virtual void OnWindowSurfaceChanged(const cc::SurfaceInfo& surface_info) {}
+
  protected:
   ~WindowDelegate() override {}
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_DELEGATE_H_