Add "open as window" menu item to NTP app menu.

chrome/browser/extensions/extension_process_manager.cc

Index: chrome/browser/extensions/extension_process_manager.cc
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index 8fd5538c62bc446cbb88a486eb3cb28a6cc3a707..c273033a05bcd92661b5a4f87aaa42777cbb5861 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -279,10 +279,11 @@ void ExtensionProcessManager::Observe(NotificationType type,
                                       const NotificationSource& source,
                                       const NotificationDetails& details) {
   switch (type.value) {
-    case NotificationType::EXTENSIONS_READY:
+    case NotificationType::EXTENSIONS_READY: {
       CreateBackgroundHosts(this,
           Source<Profile>(source).ptr()->GetExtensionsService()->extensions());
       break;
+    }
 
     case NotificationType::EXTENSION_LOADED: {
       ExtensionsService* service =
@@ -452,6 +453,9 @@ void IncognitoExtensionProcessManager::Observe(
       // it matches our profile.
       Browser* browser = Source<Browser>(source).ptr();
       if (browser->profile() == browsing_instance_->profile()) {
+        // On Chrome OS, a login screen is implemented as a browser.
+        // This browser has no extension service.  In this case,
+        // service will be NULL.
         ExtensionsService* service =
             browsing_instance_->profile()->GetExtensionsService();
         if (service && service->is_ready())