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

ui/views/mus/window_manager_connection.h

Index: ui/views/mus/window_manager_connection.h
diff --git a/ui/views/mus/window_manager_connection.h b/ui/views/mus/window_manager_connection.h
index 049e09509afb35c23ca2f7a6217e4d5e65610778..0b39b10c96f73fd8048a596b76bb4e9fa72b4a64 100644
--- a/ui/views/mus/window_manager_connection.h
+++ b/ui/views/mus/window_manager_connection.h
@@ -41,13 +41,13 @@ class VIEWS_MUS_EXPORT WindowManagerConnection
     : public NON_EXPORTED_BASE(mus::WindowTreeDelegate),
       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_; }
 
@@ -67,7 +67,6 @@ class VIEWS_MUS_EXPORT WindowManagerConnection
 
   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();
@@ -87,6 +86,7 @@ class VIEWS_MUS_EXPORT WindowManagerConnection
   std::unique_ptr<mus::WindowTreeConnection> window_tree_connection_;
   // Must be empty on destruction.
   base::ObserverList<PointerWatcher, true> pointer_watchers_;
+  bool created_device_data_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManagerConnection);
 };