Make Mac menu code obey incognito availability.

chrome/browser/ui/cocoa/history_menu_cocoa_controller.mm

 // Copyright (c) 2012 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/ui/cocoa/history_menu_cocoa_controller.h"
 
 #include "base/memory/scoped_vector.h"
 #include "chrome/app/chrome_command_ids.h"  // IDC_HISTORY_MENU
 #import "chrome/browser/app_controller_mac.h"
 #include "chrome/browser/history/history.h"
@@ skipping 16 matching lines @@
 - (id)initWithBridge:(HistoryMenuBridge*)bridge {
   if ((self = [super init])) {
     bridge_ = bridge;
     DCHECK(bridge_);
   }
   return self;
 }
 
 - (BOOL)validateMenuItem:(NSMenuItem*)menuItem {
   AppController* controller = [NSApp delegate];
-  return [controller keyWindowIsNotModal];
+  return ![controller keyWindowIsModal];
 }
 
 // Open the URL of the given history item in the current tab.
 - (void)openURLForItem:(const HistoryMenuBridge::HistoryItem*)node {
   Browser* browser =
       chrome::FindOrCreateTabbedBrowser(bridge_->profile(),
                                         chrome::HOST_DESKTOP_TYPE_NATIVE);
   WindowOpenDisposition disposition =
       event_utils::WindowOpenDispositionFromNSEvent([NSApp currentEvent]);
 
@@ skipping 13 matching lines @@
   }
 }
 
 - (IBAction)openHistoryMenuItem:(id)sender {
   const HistoryMenuBridge::HistoryItem* item =
       bridge_->HistoryItemForMenuItem(sender);
   [self openURLForItem:item];
 }
 
 @end  // HistoryMenuCocoaController