Makes Panel related classes use ash/wm/common types

ash/wm/drag_window_resizer.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_DRAG_WINDOW_RESIZER_H_
 #define ASH_WM_DRAG_WINDOW_RESIZER_H_
 
 #include <memory>
 
 #include "ash/wm/window_resizer.h"
@@ skipping 34 matching lines @@
   explicit DragWindowResizer(WindowResizer* next_window_resizer,
                              wm::WindowState* window_state);
 
   // Updates the bounds of the drag window for window dragging.
   void UpdateDragWindow(const gfx::Rect& bounds_in_parent,
                         const gfx::Point& drag_location_in_screen);
 
   // Returns true if we should allow the mouse pointer to warp.
   bool ShouldAllowMouseWarp();
 
+  aura::Window* GetAuraTarget();
+
   std::unique_ptr<WindowResizer> next_window_resizer_;
 
   // Shows a semi-transparent image of the window being dragged.
   std::unique_ptr<DragWindowController> drag_window_controller_;
 
   gfx::Point last_mouse_location_;
 
   // Current instance for use by the DragWindowResizerTest.
   static DragWindowResizer* instance_;
 
   base::WeakPtrFactory<DragWindowResizer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DragWindowResizer);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_DRAG_WINDOW_RESIZER_H_