[Mac] Enable click-drag-release behavior in the Wrench menu's custom items.

chrome/browser/cocoa/menu_tracked_button.h

+// 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.
+
+#ifndef CHROME_BROWSER_COCOA_MENU_TRACKED_BUTTON_H_
+#define CHROME_BROWSER_COCOA_MENU_TRACKED_BUTTON_H_
+#pragma once
+
+#import <Cocoa/Cocoa.h>
+
+// A MenuTrackedButton is meant to be used whenever a button is placed inside
+// the custom view of an NSMenuItem. If the user opens the menu in a non-sticky
+// fashion (i.e. clicks, holds, and drags) and then releases the mouse over
+// a MenuTrackedButton, it will |-performClick:| itself.
+@interface MenuTrackedButton : NSButton {
+ @private
+  // If the button received a |-mouseEntered:| event. This short-circuits the
+  // custom drag tracking logic.
+  BOOL didEnter_;
+
+  // Whether or not the user is in a click-drag-release event sequence. If so
+  // and this receives a |-mouseUp:|, then this will click itself.
+  BOOL tracking_;
+}
+
+@end
+
+#endif  // CHROME_BROWSER_COCOA_MENU_TRACKED_BUTTON_H_