mac: Update clients of scoped_nsobject.h.

chrome/browser/ui/cocoa/draggable_button.mm

 // Copyright (c) 2011 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.
 
 #import "chrome/browser/ui/cocoa/draggable_button.h"
 
 #include "base/logging.h"
 
 @implementation DraggableButton
 
@@ skipping 21 matching lines @@
   if ([draggableButtonImpl_ mouseUpImpl:theEvent] ==
           kDraggableButtonMixinCallSuper) {
     [super mouseUp:theEvent];
   }
 }
 
 - (void)mouseDown:(NSEvent*)theEvent {
   // The impl spins an event loop to distinguish clicks from drags,
   // which could result in our destruction.  Wire ourselves down for
   // the duration.
-  scoped_nsobject<DraggableButton> keepAlive([self retain]);
+  base::scoped_nsobject<DraggableButton> keepAlive([self retain]);
 
   if ([draggableButtonImpl_ mouseDownImpl:theEvent] ==
           kDraggableButtonMixinCallSuper) {
     [super mouseDown:theEvent];
   }
 }
 
 - (void)beginDrag:(NSEvent*)dragEvent {
   // Must be overridden by subclasses.
   NOTREACHED();
 }
 
 @end  // @interface DraggableButton