[Mac] Don't disable all menu items if there isn't a browser window open.

chrome/browser/app_controller_mac.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/app_controller_mac.h"
 
 #include "app/l10n_util_mac.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/mac_util.h"
@@ skipping 562 matching lines @@
   TabRestoreService* service = [self defaultProfile]->GetTabRestoreService();
   return service && !service->entries().empty();
 }
 
 // Returns true if there is not a modal window (either window- or application-
 // modal) blocking the active browser. Note that tab modal dialogs (HTTP auth
 // sheets) will not count as blocking the browser. But things like open/save
 // dialogs that are window modal will block the browser.
 - (BOOL)keyWindowIsNotModal {
   Browser* browser = BrowserList::GetLastActive();
-  return [NSApp modalWindow] == nil && (browser &&
+  return [NSApp modalWindow] == nil && (!browser ||
          ![[browser->window()->GetNativeHandle() attachedSheet]
              isKindOfClass:[NSWindow class]]);
 }
 
 // Called to validate menu items when there are no key windows. All the
 // items we care about have been set with the |commandDispatch:| action and
 // a target of FirstResponder in IB. If it's not one of those, let it
 // continue up the responder chain to be handled elsewhere. We pull out the
 // tag as the cross-platform constant to differentiate and dispatch the
 // various commands.
@@ skipping 436 matching lines @@
   [appController showPreferencesWindow:nil page:page profile:profile];
 }
 
 namespace app_controller_mac {
 
 bool IsOpeningNewWindow() {
   return g_is_opening_new_window;
 }
 
 }  // namespace app_controller_mac