Revert of Remove NPAPI plugin from chromoting webapp.

remoting/webapp/host_it2me_dispatcher.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.
 
 /**
  * @fileoverview
  * This class provides an interface between the HostSession and either the
- * NativeMessaging Host
+ * NativeMessaging Host or the Host NPAPI plugin, depending on whether or not
+ * NativeMessaging is supported. Since the test for NativeMessaging support is
+ * asynchronous, the connection is attemped on either the the NativeMessaging
+ * host or the NPAPI plugin once the test is complete.
  *
- * TODO(sergeyu): Remove this class.
+ * TODO(sergeyu): Remove this class once the NPAPI plugin is dropped.
  */
 
 'use strict';
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /**
  * @constructor
  */
 remoting.HostIt2MeDispatcher = function() {
   /**
    * @type {remoting.HostIt2MeNativeMessaging}
    * @private */
   this.nativeMessagingHost_ = null;
 
   /**
+   * @type {remoting.HostPlugin}
+   * @private */
+  this.npapiHost_ = null;
+
+  /**
    * @param {remoting.Error} error
    * @private */
   this.onErrorHandler_ = function(error) {}
 };
 
 /**
+ * @param {function():remoting.HostPlugin} createPluginCallback Callback to
+ *     instantiate the NPAPI plugin when NativeMessaging is determined to be
+ *     unsupported.
  * @param {function():void} onDispatcherInitialized Callback to be called after
  *     initialization has finished successfully.
  * @param {function(remoting.Error):void} onDispatcherInitializationFailed
  *     Callback to invoke if neither the native messaging host nor the NPAPI
  *     plugin works.
  */
 remoting.HostIt2MeDispatcher.prototype.initialize =
-    function(onDispatcherInitialized,
+    function(createPluginCallback, onDispatcherInitialized,
              onDispatcherInitializationFailed) {
   /** @type {remoting.HostIt2MeDispatcher} */
   var that = this;
 
   function onNativeMessagingStarted() {
+    console.log('Native Messaging supported.');
+
+    that.npapiHost_ = null;
     onDispatcherInitialized();
   }
 
   function onNativeMessagingInitFailed() {
+    console.log('Native Messaging unsupported, falling back to NPAPI.');
+
     that.nativeMessagingHost_ = null;
-    onDispatcherInitializationFailed(remoting.Error.MISSING_PLUGIN);
+    that.npapiHost_ = createPluginCallback();
+
+    // TODO(weitaosu): is there a better way to check whether NPAPI plugin is
+    // supported?
+    if (that.npapiHost_) {
+      onDispatcherInitialized();
+    } else {
+      onDispatcherInitializationFailed(remoting.Error.MISSING_PLUGIN);
+    }
   }
 
   this.nativeMessagingHost_ = new remoting.HostIt2MeNativeMessaging();
   this.nativeMessagingHost_.initialize(onNativeMessagingStarted,
                                        onNativeMessagingInitFailed,
                                        this.onNativeMessagingError_.bind(this));
 }
 
 /**
  * @param {remoting.Error} error
  */
 remoting.HostIt2MeDispatcher.prototype.onNativeMessagingError_ =
     function(error) {
   this.nativeMessagingHost_ = null;
   this.onErrorHandler_(error);
 }
 
 /**
+ * @return {boolean}
+ */
+remoting.HostIt2MeDispatcher.prototype.usingNpapi = function() {
+  return this.npapiHost_ != null;
+}
+
+/**
+ * @return {remoting.HostPlugin}
+ */
+remoting.HostIt2MeDispatcher.prototype.getNpapiHost = function() {
+  return this.npapiHost_;
+}
+
+/**
  * @param {string} email The user's email address.
  * @param {string} authServiceWithToken Concatenation of the auth service
  *     (e.g. oauth2) and the access token.
  * @param {function(remoting.HostSession.State):void} onStateChanged Callback to
  *     invoke when the host state changes.
  * @param {function(boolean):void} onNatPolicyChanged Callback to invoke when
  *     the nat traversal policy changes.
  * @param {function(string):void} logDebugInfo Callback allowing the plugin
  *     to log messages to the debug log.
  * @param {string} xmppServerAddress XMPP server host name (or IP address) and
  *     port.
  * @param {boolean} xmppServerUseTls Whether to use TLS on connections to the
  *     XMPP server
  * @param {string} directoryBotJid XMPP JID for the remoting directory server
  *     bot.
  * @param {function(remoting.Error):void} onError Callback to invoke in case of
  *     an error.
  */
 remoting.HostIt2MeDispatcher.prototype.connect =
     function(email, authServiceWithToken, onStateChanged,
              onNatPolicyChanged, logDebugInfo, xmppServerAddress,
              xmppServerUseTls, directoryBotJid, onError) {
   this.onErrorHandler_ = onError;
   if (this.nativeMessagingHost_) {
     this.nativeMessagingHost_.connect(
         email, authServiceWithToken, onStateChanged, onNatPolicyChanged,
         xmppServerAddress, xmppServerUseTls, directoryBotJid);
+  } else if (this.npapiHost_) {
+    this.npapiHost_.xmppServerAddress = xmppServerAddress;
+    this.npapiHost_.xmppServerUseTls = xmppServerUseTls;
+    this.npapiHost_.directoryBotJid = directoryBotJid;
+    this.npapiHost_.onStateChanged = onStateChanged;
+    this.npapiHost_.onNatTraversalPolicyChanged = onNatPolicyChanged;
+    this.npapiHost_.logDebugInfo = logDebugInfo;
+    this.npapiHost_.localize(chrome.i18n.getMessage);
+    this.npapiHost_.connect(email, authServiceWithToken);
   } else {
     console.error(
         'remoting.HostIt2MeDispatcher.connect() without initialization.');
     onError(remoting.Error.UNEXPECTED);
   }
 };
 
 /**
  * @return {void}
  */
 remoting.HostIt2MeDispatcher.prototype.disconnect = function() {
-  this.nativeMessagingHost_.disconnect();
+  if (this.npapiHost_) {
+    this.npapiHost_.disconnect();
+  } else {
+    this.nativeMessagingHost_.disconnect();
+  }
 };
 
 /**
  * @return {string} The access code generated by the it2me host.
  */
 remoting.HostIt2MeDispatcher.prototype.getAccessCode = function() {
-  return this.nativeMessagingHost_.getAccessCode();
+  if (this.npapiHost_) {
+    return this.npapiHost_.accessCode;
+  } else {
+    return this.nativeMessagingHost_.getAccessCode();
+  }
 };
 
 /**
  * @return {number} The access code lifetime, in seconds.
  */
 remoting.HostIt2MeDispatcher.prototype.getAccessCodeLifetime = function() {
-  return this.nativeMessagingHost_.getAccessCodeLifetime();
+  if (this.npapiHost_) {
+    return this.npapiHost_.accessCodeLifetime;
+  } else {
+    return this.nativeMessagingHost_.getAccessCodeLifetime();
+  }
 };
 
 /**
  * @return {string} The client's email address.
  */
 remoting.HostIt2MeDispatcher.prototype.getClient = function() {
-  return this.nativeMessagingHost_.getClient();
+  if (this.npapiHost_) {
+    return this.npapiHost_.client;
+  } else {
+    return this.nativeMessagingHost_.getClient();
+  }
 };
+
+/**
+ * @return {void}
+ */
+remoting.HostIt2MeDispatcher.prototype.cleanup = function() {
+  if (this.npapiHost_) {
+    this.npapiHost_.parentNode.removeChild(this.npapiHost_);
+  }
+};