Make download items drag sources on OS X.

chrome/browser/cocoa/bookmark_button.h

Index: chrome/browser/cocoa/bookmark_button.h
diff --git a/chrome/browser/cocoa/bookmark_button.h b/chrome/browser/cocoa/bookmark_button.h
index 631a7baf427acb1067f2c814148943718f5985cc..30341666900c47bb63afdb6fb3dcd25357861f1d 100644
--- a/chrome/browser/cocoa/bookmark_button.h
+++ b/chrome/browser/cocoa/bookmark_button.h
@@ -1,26 +1,19 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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 <Cocoa/Cocoa.h>
 
+#import "chrome/browser/cocoa/draggable_button.h"
+
 @protocol BookmarkButtonDelegate;
 
 // Class for bookmark bar buttons that can be drag sources.
-@interface BookmarkButton : NSButton {
+@interface BookmarkButton : DraggableButton {
  @private
-  BOOL draggable_;     // Is this a draggable type of button?
-  BOOL mayDragStart_;  // Set to YES on mouse down, NO on up or drag.
-  BOOL beingDragged_;
   id<BookmarkButtonDelegate> delegate_;
-
-  // Initial mouse-down to prevent a hair-trigger drag.
-  NSPoint initialMouseDownLocation_;
 }
 
-// Enable or disable dragability for special buttons like "Other Bookmarks".
-@property BOOL draggable;
-
 @property(assign, nonatomic) id<BookmarkButtonDelegate> delegate;
 
 @end  // @interface BookmarkButton