Adds OnChildWindowVisibilityChanged to ui::WindowObserver

ash/mus/bridge/wm_window_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 ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_
 #define ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_
 
 #include <memory>
 
 #include "ash/common/shell_window_ids.h"
@@ skipping 244 matching lines @@
   void OnWindowSharedPropertyChanged(
       ui::Window* window,
       const std::string& name,
       const std::vector<uint8_t>* old_data,
       const std::vector<uint8_t>* new_data) override;
   void OnWindowBoundsChanged(ui::Window* window,
                              const gfx::Rect& old_bounds,
                              const gfx::Rect& new_bounds) override;
   void OnWindowDestroying(ui::Window* window) override;
   void OnWindowDestroyed(ui::Window* window) override;
-  void OnWindowVisibilityChanging(ui::Window* window) override;
-  void OnWindowVisibilityChanged(ui::Window* window) override;
+  void OnWindowVisibilityChanging(ui::Window* window, bool visible) override;
+  void OnWindowVisibilityChanged(ui::Window* window, bool visible) override;
   void OnTransientChildAdded(ui::Window* window,
                              ui::Window* transient) override;
   void OnTransientChildRemoved(ui::Window* window,
                                ui::Window* transient) override;
 
   ui::Window* window_;
 
   // The shell window id of this window. Shell window ids are defined in
   // ash/common/shell_window_ids.h.
   int shell_window_id_ = kShellWindowId_Invalid;
@@ skipping 32 matching lines @@
 
   bool locked_to_root_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(WmWindowMus);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_BRIDGE_WM_WINDOW_MUS_H_