views/mus: Have explicit ownership of views::WindowManagerConnection.

ui/views/mus/window_manager_connection.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 UI_VIEWS_MUS_WINDOW_MANAGER_CONNECTION_H_
 #define UI_VIEWS_MUS_WINDOW_MANAGER_CONNECTION_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 23 matching lines @@
 // . Creates and owns a WindowTreeClient.
 // . Registers itself as the factory for creating NativeWidgets so that a
 //   NativeWidgetMus is created.
 // WindowManagerConnection is a singleton and should be created early on.
 //
 // TODO(sky): this name is now totally confusing. Come up with a better one.
 class VIEWS_MUS_EXPORT WindowManagerConnection
     : public NON_EXPORTED_BASE(mus::WindowTreeClientDelegate),
       public ScreenMusDelegate {
  public:
-  static void Create(shell::Connector* connector,
-                     const shell::Identity& identity);
+  static std::unique_ptr<WindowManagerConnection> Create(
+      shell::Connector* connector,
+      const shell::Identity& identity);
   static WindowManagerConnection* Get();
   static bool Exists();
 
-  // Destroys the singleton instance.
-  static void Reset();
+  ~WindowManagerConnection() override;
 
   shell::Connector* connector() { return connector_; }
 
   mus::Window* NewWindow(const std::map<std::string,
                          std::vector<uint8_t>>& properties);
 
   NativeWidget* CreateNativeWidgetMus(
       const std::map<std::string, std::vector<uint8_t>>& properties,
       const Widget::InitParams& init_params,
       internal::NativeWidgetDelegate* delegate);
 
   void AddPointerWatcher(PointerWatcher* watcher);
   void RemovePointerWatcher(PointerWatcher* watcher);
 
  private:
   friend class WindowManagerConnectionTest;
 
   WindowManagerConnection(shell::Connector* connector,
                           const shell::Identity& identity);
-  ~WindowManagerConnection() override;
 
   // Returns true if there is one or more pointer watchers for this client.
   bool HasPointerWatcher();
 
   // mus::WindowTreeClientDelegate:
   void OnEmbed(mus::Window* root) override;
   void OnWindowTreeClientDestroyed(mus::WindowTreeClient* client) override;
   void OnEventObserved(const ui::Event& event, mus::Window* target) override;
 
   // ScreenMusDelegate:
   void OnWindowManagerFrameValuesChanged() override;
   gfx::Point GetCursorScreenPoint() override;
 
   shell::Connector* connector_;
   shell::Identity identity_;
   std::unique_ptr<ScreenMus> screen_;
   std::unique_ptr<mus::WindowTreeClient> client_;
   // Must be empty on destruction.
   base::ObserverList<PointerWatcher, true> pointer_watchers_;
   bool created_device_data_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManagerConnection);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_MUS_WINDOW_MANAGER_CONNECTION_H_