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

chrome/browser/background_application_list_model.cc

Index: chrome/browser/background_application_list_model.cc
diff --git a/chrome/browser/background_application_list_model.cc b/chrome/browser/background_application_list_model.cc
index 63f2b942758ce71552b2c521e7def7fe439741c6..64ccf2e7dd96084772936c74e38b17772ec4f8e5 100644
--- a/chrome/browser/background_application_list_model.cc
+++ b/chrome/browser/background_application_list_model.cc
@@ -242,6 +242,7 @@ void BackgroundApplicationListModel::Observe(
   ExtensionsService* service = profile_->GetExtensionsService();
   if (!service || !service->is_ready())
     return;
+
   switch (type.value) {
     case NotificationType::EXTENSION_LOADED:
       OnExtensionLoaded(Details<Extension>(details).ptr());
@@ -286,7 +287,6 @@ void BackgroundApplicationListModel::RemoveObserver(Observer* observer) {
 // each observer.
 void BackgroundApplicationListModel::Update() {
   ExtensionsService* service = profile_->GetExtensionsService();
-  DCHECK(service->is_ready());
 
   // Discover current background applications, compare with previous list, which
   // is consistently sorted, and notify observers if they differ.