Mac: Fix for janky tab dragging/reordering.

chrome/browser/ui/cocoa/tabs/tab_strip_drag_controller.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_COCOA_TABS_TAB_STRIP_DRAG_CONTROLLER_H_
 #define CHROME_BROWSER_UI_COCOA_TABS_TAB_STRIP_DRAG_CONTROLLER_H_
 
 #import <Cocoa/Cocoa.h>
 #include <map>
 
@@ skipping 41 matching lines @@
 
   TabController* draggedTab_;  // Weak. The tab controller being dragged.
 
   TabWindowController* draggedController_;  // Weak. Controller being dragged.
   NSWindow* dragWindow_;  // Weak. The window being dragged
   NSWindow* dragOverlay_;  // Weak. The overlay being dragged
 
   TabWindowController* targetController_;  // weak. Controller being targeted
 }
 
+// The tab being dragged, or nil if not dragging a tab.
+@property(readonly) TabController* draggedTab;
+
 // Designated initializer.
 - (id)initWithTabStripController:(TabStripController*)controller;
 
 // TabDraggingEventTarget methods are also implemented.
 
 @end
 
 #endif  // CHROME_BROWSER_UI_COCOA_TABS_TAB_STRIP_DRAG_CONTROLLER_H_