Close mirroring window only when necessary

ash/display/mirror_window_controller.h

 // Copyright (c) 2013 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_DISPLAY_MIRROR_WINDOW_CONTROLLER_H_
 #define ASH_DISPLAY_MIRROR_WINDOW_CONTROLLER_H_
 
 #include <map>
 #include <vector>
 
 #include "ash/ash_export.h"
+#include "ash/display/display_manager.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host_observer.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace aura {
 class Window;
@@ skipping 28 matching lines @@
   ~MirrorWindowController() override;
 
   // Updates the root window's bounds using |display_info|.
   // Creates the new root window if one doesn't exist.
   void UpdateWindow(const std::vector<DisplayInfo>& display_info);
 
   // Same as above, but using existing display info
   // for the mirrored display.
   void UpdateWindow();
 
-  // Close the mirror window.
-  void Close();
+  // Close the mirror window if they're not necessary any longer.
+  void CloseIfNotNecessary();
 
   // aura::WindowTreeHostObserver overrides:
   void OnHostResized(const aura::WindowTreeHost* host) override;
 
   // Return the root window used to mirror the content. NULL if the
   // display is not mirrored by the compositor path.
   aura::Window* GetWindow();
 
   // Returns the gfx::Display for the mirroring root window.
   gfx::Display GetDisplayForRootWindow(const aura::Window* root) const;
 
   // Returns the AshWindwoTreeHost created for |display_id|.
   AshWindowTreeHost* GetAshWindowTreeHostForDisplayId(int64 display_id);
 
   // Returns all root windows hosting mirroring displays.
   aura::Window::Windows GetAllRootWindows() const;
 
  private:
   friend class test::MirrorWindowTestApi;
 
   struct MirroringHostInfo;
 
-  void CloseAndDeleteHost(MirroringHostInfo* host_info);
+  // Close the mirror window. When |delay_host_deletion| is true, the window
+  // tree host will be deleted in an another task on UI thread. This is
+  // necessary to safely delete the WTH that is currently handling input events.
+  void Close(bool delay_host_deletion);
+
+  void CloseAndDeleteHost(MirroringHostInfo* host_info,
+                          bool delay_host_deletion);
 
   // Creates a RootWindowTransformer for current display
   // configuration.
   scoped_ptr<RootWindowTransformer> CreateRootWindowTransformer() const;
 
   typedef std::map<int64_t, MirroringHostInfo*> MirroringHostInfoMap;
   MirroringHostInfoMap mirroring_host_info_map_;
 
+  DisplayManager::MultiDisplayMode multi_display_mode_;
+
   scoped_ptr<aura::client::ScreenPositionClient> screen_position_client_;
 
   scoped_ptr<ui::Reflector> reflector_;
 
   DISALLOW_COPY_AND_ASSIGN(MirrorWindowController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_MIRROR_WINDOW_CONTROLLER_H_