[Mac] Disable menu certain menu items when a modal dialog or sheet is present.

chrome/browser/app_controller_mac.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_APP_CONTROLLER_MAC_H_
 #define CHROME_BROWSER_APP_CONTROLLER_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <vector>
 
@@ skipping 45 matching lines @@
 - (void)didEndMainMessageLoop;
 - (Profile*)defaultProfile;
 
 // Try to close all browser windows, and if that succeeds then quit.
 - (BOOL)tryToTerminateApplication:(NSApplication*)app;
 
 // Stop trying to terminate the application. That is, prevent the final browser
 // window closure from causing the application to quit.
 - (void)stopTryingToTerminateApplication:(NSApplication*)app;
 
+// 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;
+
 // Show the preferences window, or bring it to the front if it's already
 // visible.
 - (IBAction)showPreferences:(id)sender;
 
 // Redirect in the menu item from the expected target of "File's
 // Owner" (NSAppliation) for a Branded About Box
 - (IBAction)orderFrontStandardAboutPanel:(id)sender;
 
 // Delegate method to return the dock menu.
 - (NSMenu*)applicationDockMenu:(NSApplication*)sender;
 
 // Get the URLs that Launch Services expects the browser to open at startup.
 - (const std::vector<GURL>&)startupUrls;
 
 // Clear the list of startup URLs.
 - (void)clearStartupUrls;
 
 @end
 
 #endif