[Refactor] Kill some dead code because it is no longer possible to drag maximized windows

ash/wm/drag_details.h

 // Copyright 2014 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_DETAILS_H_
 #define ASH_WM_DRAG_DETAILS_H_
 
 #include "ash/ash_export.h"
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/client/window_move_client.h"
 #include "ui/gfx/rect.h"
 
 namespace aura {
 class Window;
 }
 
 namespace ash {
-class WindowResizer;
 
 namespace wm {
 class WindowState;
 }
 
 struct ASH_EXPORT DragDetails {
   DragDetails(aura::Window* window,
               const gfx::Point& location,
               int window_component,
               aura::client::WindowMoveSource source);
@@ skipping 25 matching lines @@
   const int size_change_direction;
 
   // Will the drag actually modify the window?
   const bool is_resizable;
 
   // Source of the event initiating the drag.
   const aura::client::WindowMoveSource source;
 
   // True if the window should attach to the shelf after releasing.
   bool should_attach_to_shelf;
-
-  // WindowResizer that is controlling the drag.
-  WindowResizer* window_resizer;
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_DRAG_DETAILS_H_