Move mojo/application/public -> mojo/shell/public

mojo/application/public/interfaces/content_handler.mojom

-// Copyright 2014 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.
-
-module mojo;
-
-import "mojo/application/public/interfaces/application.mojom";
-import "network/public/interfaces/url_loader.mojom";
-
-// Interface implemented by content handlers. To avoid race conditions with
-// dropped requests, the implementation should keep a reference to the lifetime
-// of the app (by holding on to AppRefCount). Each application started by
-// StartApplication should call the callback given by that method on
-// destruction. When the owner in the shell notices this, it will destroy the
-// interface pointer, which should cause the strongly-bound ContentHandler
-// implementation to self destruct and release the app reference.
-interface ContentHandler {
-  // The callback should be called when the application is destructed.
-  StartApplication(Application& application, URLResponse response) => ();
-};