Implement FallbackSignalStrategy.

remoting/webapp/crd/js/signal_strategy.js

 // 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.
 
 'use strict';
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /**
  * Abstract interface for various signaling mechanisms.
  *
  * @interface
  * @extends {base.Disposable}
  */
 remoting.SignalStrategy = function() {};
 
 /**
  * @enum {number} SignalStrategy states. Possible state transitions:
  *    NOT_CONNECTED -> CONNECTING (connect() called).
  *    CONNECTING -> HANDSHAKE (connected successfully).
  *    HANDSHAKE -> CONNECTED (authenticated successfully).
  *    CONNECTING -> FAILED (connection failed).
  *    HANDSHAKE -> FAILED (authentication failed).
  *    * -> CLOSED (dispose() called).
+ *
+ * Do not re-order these values without updating fallback_signal_strategy.js.
  */
 remoting.SignalStrategy.State = {
   NOT_CONNECTED: 0,
   CONNECTING: 1,
   HANDSHAKE: 2,
   CONNECTED: 3,
   FAILED: 4,
   CLOSED: 5
 };
 
@@ skipping 33 matching lines @@
 /**
  * Creates the appropriate signal strategy for the current environment.
  * @param {function(remoting.SignalStrategy.State): void} onStateChangedCallback
  * @return {remoting.SignalStrategy} New signal strategy object.
  */
 remoting.SignalStrategy.create = function(onStateChangedCallback) {
   // Only use XMPP when TCP API is available and TLS support is enabled. That's
   // not the case for V1 app (socket API is available only to platform apps)
   // and for Chrome releases before 38.
   if (chrome.socket && chrome.socket.secure) {
-    return new remoting.XmppConnection(onStateChangedCallback);
+    return new remoting.FallbackSignalStrategy(
+        /**
+         * @param {function(remoting.SignalStrategy.State): void}
+         *     onStateChangedCallback_
+         */
+        function(onStateChangedCallback_) {

[Sergey Ulanov, 2015/01/13 19:43:51]

here and below: remove _ suffix from the name

[Sergey Ulanov, 2015/01/13 19:43:51]

Maybe move this function out of the argument list, to make this code more
readable.

[Jamie, 2015/01/14 01:36:26]

Done.

[Jamie, 2015/01/14 01:36:26]

Done.

+          return new remoting.XmppConnection(onStateChangedCallback_);
+        },
+        /**
+         * @param {function(remoting.SignalStrategy.State): void}
+         *     onStateChangedCallback_
+         */
+        function(onStateChangedCallback_) {
+          return new remoting.WcsAdapter(onStateChangedCallback_);
+        },
+        onStateChangedCallback,
+        /**
+         * @param {remoting.FallbackSignalStrategy.Result} progress
+         */
+        function(progress) {
+          console.warn('FallbackStrategyProgress: ' + progress);
+        });
   } else {
     return new remoting.WcsAdapter(onStateChangedCallback);
   }
 };