Store the result of Pass() in a local variable.

ash/drag_drop/drag_drop_controller.cc

 // 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.
 
 #include "ash/drag_drop/drag_drop_controller.h"
 
 #include "ash/drag_drop/drag_drop_tracker.h"
 #include "ash/drag_drop/drag_image_view.h"
 #include "ash/shell.h"
 #include "base/bind.h"
@@ skipping 539 matching lines @@
   if (drag_source_window_)
     drag_source_window_->RemoveObserver(this);
   drag_source_window_ = NULL;
 }
 
 void DragDropController::Cleanup() {
   if (drag_window_)
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
-  // Cleanup can be called again while deleting DragDropTracker, so use Pass
-  // instead of reset to avoid double free.
-  drag_drop_tracker_.Pass();
+  // Cleanup can be called again while deleting DragDropTracker, so delete
+  // the pointer with a local variable to avoid double free.
+  scoped_ptr<ash::DragDropTracker> holder = drag_drop_tracker_.Pass();
 }
 
 }  // namespace ash