mojo: terminate apps if the shell goes away

mojo/shell/context.h

Index: mojo/shell/context.h
diff --git a/mojo/shell/context.h b/mojo/shell/context.h
index 7cb288f1c7ddc040b4f516d4f23e80f73f008a4f..544f66ab771ced8771e79704421e2b643c41a0e3 100644
--- a/mojo/shell/context.h
+++ b/mojo/shell/context.h
@@ -31,9 +31,6 @@ class Context {
   ~Context();
 
   void Init();
-  // Tear down context in safe order prior to deleting. Shutdown() is also
-  // called by the destructor.
-  void Shutdown();
 
   TaskRunners* task_runners() { return task_runners_.get(); }
   ServiceManager* service_manager() { return &service_manager_; }