Gets mash to use WmToplevelWindowEventHandler

ash/wm/common/wm_toplevel_window_event_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_WM_TOPLEVEL_WINDOW_EVENT_HANDLER_H_
 #define ASH_WM_WM_TOPLEVEL_WINDOW_EVENT_HANDLER_H_
 
 #include <memory>
 
 #include "ash/wm/common/ash_wm_common_export.h"
@@ skipping 50 matching lines @@
   // not run if the drag does not start.
   bool AttemptToStartDrag(WmWindow* window,
                           const gfx::Point& point_in_parent,
                           int window_component,
                           aura::client::WindowMoveSource source,
                           const EndClosure& end_closure);
 
   // If there is a drag in progress it is reverted, otherwise does nothing.
   void RevertDrag();
 
+  // Returns true if there is a drag in progress.
+  bool is_drag_in_progress() const { return window_resizer_.get() != nullptr; }
+
  private:
   class ScopedWindowResizer;
 
   // Completes or reverts the drag if one is in progress. Returns true if a
   // drag was completed or reverted.
   bool CompleteDrag(DragResult result);
 
   void HandleMousePressed(WmWindow* target, ui::MouseEvent* event);
   void HandleMouseReleased(WmWindow* target, ui::MouseEvent* event);
 
@@ skipping 38 matching lines @@
 
   EndClosure end_closure_;
 
   DISALLOW_COPY_AND_ASSIGN(WmToplevelWindowEventHandler);
 };
 
 }  // namespace wm
 }  // namespace ash
 
 #endif  // ASH_WM_WM_TOPLEVEL_WINDOW_EVENT_HANDLER_H_