Get rid of KeepAlive. Quit shell when all urls run directly by Context are closed.

mojo/application_manager/application_manager.cc

Index: mojo/application_manager/application_manager.cc
diff --git a/mojo/application_manager/application_manager.cc b/mojo/application_manager/application_manager.cc
index 1a75caebba29b0cde1d7d222fc44aaaaa91ca8bb..3eea637ae6c853ce6517b290243fec86a70de859 100644
--- a/mojo/application_manager/application_manager.cc
+++ b/mojo/application_manager/application_manager.cc
@@ -148,7 +148,9 @@ bool ApplicationManager::TestAPI::HasFactoryForURL(const GURL& url) const {
 }
 
 ApplicationManager::ApplicationManager()
-    : interceptor_(NULL), weak_ptr_factory_(this) {
+    : delegate_(NULL),
+      interceptor_(NULL),
+      weak_ptr_factory_(this) {
 }
 
 ApplicationManager::~ApplicationManager() {
@@ -285,6 +287,8 @@ void ApplicationManager::OnShellImplError(ShellImpl* shell_impl) {
   ApplicationLoader* loader = GetLoaderForURL(url);
   if (loader)
     loader->OnServiceError(this, url);
+  if (delegate_)
+    delegate_->OnServiceError(url);
 }
 
 ScopedMessagePipeHandle ApplicationManager::ConnectToServiceByName(