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

chrome/browser/cocoa/menu_tracked_button.mm

+// 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 "chrome/browser/cocoa/menu_tracked_button.h"
+
+@implementation MenuTrackedButton
+
+- (void)mouseEntered:(NSEvent*)theEvent {
+  didEnter_ = YES;
+  [super mouseEntered:theEvent];
+}
+
+- (void)mouseExited:(NSEvent*)theEvent {
+  didEnter_ = NO;
+  tracking_ = NO;
+  [super mouseExited:theEvent];
+}
+
+- (void)mouseDragged:(NSEvent*)theEvent {
+  tracking_ = !didEnter_;
+  [super mouseDragged:theEvent];
+}
+
+- (void)mouseUp:(NSEvent*)theEvent {
+  if (!tracking_) {
+    return [super mouseUp:theEvent];
+  }
+  [self performClick:self];
+}
+
+@end