Mac: implement drag-and-drop of URLs to tabs/tab strip.

chrome/browser/cocoa/tab_strip_view.h

 // Copyright (c) 2009 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 CHROME_BROWSER_COCOA_TAB_STRIP_VIEW_H_
 #define CHROME_BROWSER_COCOA_TAB_STRIP_VIEW_H_
 
 #import <Cocoa/Cocoa.h>
 
+#include "base/scoped_nsobject.h"
+#import "chrome/browser/cocoa/url_drop_target.h"
+
 // A view class that handles rendering the tab strip
 
 @interface TabStripView : NSView {
  @private
   NSTimeInterval lastMouseUp_;
 
+  // Handles being a drag-and-drop target.
+  scoped_nsobject<URLDropTargetHandler> dropHandler_;
+
   // Weak; the following come from the nib.
   NSButton* newTabButton_;
 }
 
 @property(assign, nonatomic) IBOutlet NSButton* newTabButton;
 
 @end
 
 #endif  // CHROME_BROWSER_COCOA_TAB_STRIP_VIEW_H_