UMA data collection for docked windows

ash/wm/dock/docked_window_resizer.h

 // Copyright (c) 2013 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_DOCK_DOCK_WINDOW_RESIZER_H_
 #define ASH_WM_DOCK_DOCK_WINDOW_RESIZER_H_
 
 #include "ash/wm/dock/dock_types.h"
 #include "ash/wm/window_resizer.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
 
 namespace gfx {
 class Point;
 class Rect;
 }
 
 namespace aura {
 class RootWindow;
 }
 
@@ skipping 40 matching lines @@
   void StartedDragging();
 
   // Informs the DockLayoutManager that the drag is complete if it was informed
   // of the drag start.
   void FinishedDragging();
 
   const Details details_;
 
   gfx::Point last_location_;
 
+  base::Time last_docked_action_;
+
   // Wraps a window resizer and adds detaching / reattaching during drags.
   scoped_ptr<WindowResizer> next_window_resizer_;
 
   // Dock container window.
   internal::DockedWindowLayoutManager* dock_layout_;
   internal::DockedWindowLayoutManager* initial_dock_layout_;
 
   // Set to true once Drag() is invoked and the bounds of the window change.
   bool did_move_or_resize_;
 
   // Set to true if the window that is being dragged was docked before drag.
   bool was_docked_;
 
   // True if the dragged window is docked during the drag.
   bool is_docked_;
 
   base::WeakPtrFactory<DockedWindowResizer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DockedWindowResizer);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_DOCK_DOCK_WINDOW_RESIZER_H_