Implement back/forward toolbar menus on Mac....

chrome/browser/cocoa/delayedmenu_button.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_DELAYEDMENU_BUTTON_H_
+#define CHROME_BROWSER_COCOA_DELAYEDMENU_BUTTON_H_
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/scoped_nsobject.h"
+
+@interface DelayedMenuButton : NSButton {
+  NSMenu* menu_;                            // Strong (retained).
+  BOOL menuEnabled_;
+}
+
+// The menu to display. Note that it should have no (i.e., a blank) title and
+// that the 0-th entry should be blank (and won't be displayed). (This is
+// because we use a pulldown list, for which Cocoa uses the 0-th item as "title"
+// in the button. This might change if we ever switch to a pop-up. Our direct
+// use of the given NSMenu object means that the one can set and use NSMenu's
+// delegate as usual.)
+@property(retain, nonatomic) NSMenu* menu;
+
+// Is the menu enabled? (If not, don't act like a click-hold button.)
+@property(assign, nonatomic) BOOL menuEnabled;
+
+@end  // @interface DelayedMenuButton
+
+#endif  // CHROME_BROWSER_COCOA_DELAYEDMENU_BUTTON_H_