Refactor PhantomWindowController so that the PhantomWindowController owns the phantom window

ash/wm/gestures/system_pinch_handler.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 ASH_WM_GESTURES_SYSTEM_PINCH_HANDLER_H_
 #define ASH_WM_GESTURES_SYSTEM_PINCH_HANDLER_H_
 
 #include "ash/wm/workspace/phantom_window_controller.h"
+#include "base/memory/scoped_ptr.h"
 
 namespace aura {
 class Window;
 }
 
 namespace gfx {
 class Point;
 }
 
 namespace ui {
@@ skipping 38 matching lines @@
     PHANTOM_WINDOW_NORMAL,
     PHANTOM_WINDOW_MAXIMIZED,
     PHANTOM_WINDOW_MINIMIZED,
   };
 
   aura::Window* target_;
   views::Widget* widget_;
 
   // A phantom window is used to provide visual cues for
   // pinch-to-resize/maximize/minimize gestures.
-  PhantomWindowController phantom_;
+  scoped_ptr<PhantomWindowController> phantom_;
 
   // When the phantom window is in minimized or maximized state, moving the
   // target window should not move the phantom window. So |phantom_state_| is
   // used to track the state of the phantom window.
   PhantomWindowState phantom_state_;
 
   // PINCH_UPDATE events include incremental pinch-amount. But it is necessary
   // to keep track of the overall pinch-amount. |pinch_factor_| is used for
   // that.
   double pinch_factor_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemPinchHandler);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_GESTURES_SYSTEM_PINCH_HANDLER_H_