Swap main menu with app-specific menu when app window focused.

chrome/browser/ui/cocoa/apps/app_shim_menu_controller_mac.h

Index: chrome/browser/ui/cocoa/apps/app_shim_menu_controller_mac.h
diff --git a/chrome/browser/ui/cocoa/apps/app_shim_menu_controller_mac.h b/chrome/browser/ui/cocoa/apps/app_shim_menu_controller_mac.h
new file mode 100644
index 0000000000000000000000000000000000000000..111b9dedeff1286a1ac0178782fcdf376badc7e3
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+++ b/chrome/browser/ui/cocoa/apps/app_shim_menu_controller_mac.h
@@ -0,0 +1,28 @@
+// Copyright 2013 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_UI_COCOA_APPS_APP_SHIM_MENU_CONTROLLER_MAC_H_
+#define CHROME_BROWSER_UI_COCOA_APPS_APP_SHIM_MENU_CONTROLLER_MAC_H_
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/mac/scoped_nsobject.h"
+
+// This controller listens to NSWindowDidBecomeMainNotification and
+// NSWindowDidResignMainNotification and modifies the main menu bar to mimic a
+// main menu for the app. When an app window becomes main, all Chrome menu items
+// are hidden and menu items for the app are appended to the main menu. When the
+// app window resigns main, its menu items are removed and all Chrome menu items
+// are unhidden.
+@interface AppShimMenuController : NSObject {
+ @private
+  // The extension id of the currently focused packaged app.
+  base::scoped_nsobject<NSString> appId_;
+  // A menu item for the currently focused packaged app.
+  base::scoped_nsobject<NSMenuItem> appMenuItem_;
+}
+
+@end
+
+#endif  // CHROME_BROWSER_UI_COCOA_APPS_APP_SHIM_MENU_CONTROLLER_MAC_H_