[Chromoting] Move shared webapp JS files from crd/js -> base/js

remoting/webapp/crd/js/activity.js

-// Copyright 2015 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.
-
-/** @suppress {duplicate} */
-var remoting = remoting || {};
-
-(function() {
-
-'use strict';
-
-/**
- * An Activity is a responsible for
- * 1. Showing the appropriate UX to establish a connection with the host and
- *    create a remoting.ClientSession.
- * 2. Handling connection failures and retrying if necessary.
- * 3. Responding to session state changes and showing UX if necessary.
- *
- * @interface
- * @extends {base.Disposable}
- * @extends {remoting.ClientSession.EventHandler}
- */
-remoting.Activity = function() {};
-
-/**
- * Starts a new connection.
- *
- * @return {void}
- */
-remoting.Activity.prototype.start = function() {};
-
-/**
- * Cancels or disconnects a remote connection.
- * @return {void}
- */
-remoting.Activity.prototype.stop = function() {};
-
-})();