Revert 248255 "It2me native messaging host: webapp implementation."

> It2me native messaging host: webapp implementation.
> 
> The webapp implementation of the it2me native messaging is based on the me2me couterpart. But I got rid of the per-message onDone/onError callbacks because unlike me2me, all requests to the it2me host are asynchronous: direct responses to all requests are meaningless. Only the asynchronous callbacks on host state change and nat policy update need to be processed.
> 
> I verified that this is fully functional on Linux. Windows and Mac verification haven't been done and are planned after the linux work is completed.
> 
> BUG=309844
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248072
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248157
> 
> Review URL: https://codereview.chromium.org/138503009

TBR=weitaosu@chromium.org

Review URL: https://codereview.chromium.org/151853003

git-svn-id: svn://svn.chromium.org/chrome/branches/1817/src@248339 0039d316-1c4b-4281-b951-d872f2087c98

12 files changed, 68 insertions, 686 deletions

diff --git a/remoting/host/it2me/it2me_native_messaging_host_main.cc b/remoting/host/it2me/it2me_native_messaging_host_main.cc
index e052516..2dca61f 100644
--- a/remoting/host/it2me/it2me_native_messaging_host_main.cc
+++ b/remoting/host/it2me/it2me_native_messaging_host_main.cc
@@ -4,76 +4,16 @@
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
-#include "base/i18n/icu_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
-#include "media/base/media.h"
-#include "net/socket/ssl_server_socket.h"
-#include "remoting/base/breakpad.h"
-#include "remoting/base/resources.h"
 #include "remoting/host/it2me/it2me_native_messaging_host.h"
 #include "remoting/host/logging.h"
-#include "remoting/host/usage_stats_consent.h"
-
-#if defined(OS_LINUX)
-#include <gtk/gtk.h>
-#endif  // defined(OS_LINUX)
-
-#if defined(OS_MACOSX)
-#include "base/mac/scoped_nsautorelease_pool.h"
-#endif  // defined(OS_MACOSX)
-
-#if defined(OS_WIN)
-#include <commctrl.h>
-#endif  // defined(OS_WIN)
 
 namespace remoting {
 
 // Creates a It2MeNativeMessagingHost instance, attaches it to stdin/stdout and
 // runs the message loop until It2MeNativeMessagingHost signals shutdown.
 int It2MeNativeMessagingHostMain() {
-#if defined(OS_MACOSX)
-  // Needed so we don't leak objects when threads are created.
-  base::mac::ScopedNSAutoreleasePool pool;
-#endif  // defined(OS_MACOSX)
-
-#if defined(REMOTING_ENABLE_BREAKPAD)
-  // Initialize Breakpad as early as possible. On Mac the command-line needs to
-  // be initialized first, so that the preference for crash-reporting can be
-  // looked up in the config file.
-  if (IsUsageStatsAllowed()) {
-    InitializeCrashReporting();
-  }
-#endif  // defined(REMOTING_ENABLE_BREAKPAD)
-
-#if defined(OS_WIN)
-  // Register and initialize common controls.
-  INITCOMMONCONTROLSEX info;
-  info.dwSize = sizeof(info);
-  info.dwICC = ICC_STANDARD_CLASSES;
-  InitCommonControlsEx(&info);
-#endif  // defined(OS_WIN)
-
-  // Required to find the ICU data file, used by some file_util routines.
-  base::i18n::InitializeICU();
-
-  remoting::LoadResources("");
-
-  // Cannot use TOOLKIT_GTK because it is not defined when aura is enabled.
-#if defined(OS_LINUX)
-  // Required for any calls into GTK functions, such as the Disconnect and
-  // Continue windows. Calling with NULL arguments because we don't have
-  // any command line arguments for gtk to consume.
-  gtk_init(NULL, NULL);
-#endif  // OS_LINUX
-
-  // Enable support for SSL server sockets, which must be done while still
-  // single-threaded.
-  net::EnableSSLServerSockets();
-
-  // Ensures runtime specific CPU features are initialized.
-  media::InitializeCPUSpecificMediaFeatures();
-
 #if defined(OS_WIN)
   // GetStdHandle() returns pseudo-handles for stdin and stdout even if
   // the hosting executable specifies "Windows" subsystem. However the returned
@@ -108,7 +48,6 @@ int It2MeNativeMessagingHostMain() {
 
   // Run the loop until channel is alive.
   run_loop.Run();
-
   return kSuccessExitCode;
 }
 
diff --git a/remoting/host/plugin/host_script_object.cc b/remoting/host/plugin/host_script_object.cc
index 456ca50..2cbca57 100644
--- a/remoting/host/plugin/host_script_object.cc
+++ b/remoting/host/plugin/host_script_object.cc
@@ -508,7 +508,6 @@ bool HostNPScriptObject::Disconnect(const NPVariant* args,
   if (it2me_host_.get()) {
     it2me_host_->Disconnect();
     it2me_host_ = NULL;
-    host_context_.reset();
   }
 
   return true;
diff --git a/remoting/remoting_host.gypi b/remoting/remoting_host.gypi
index a6c73d7..d5dfc4a 100644
--- a/remoting/remoting_host.gypi
+++ b/remoting/remoting_host.gypi
@@ -570,32 +570,11 @@
             'host/it2me/it2me_native_messaging_host_main.cc',
           ],
           'conditions': [
-            ['OS=="linux"', {
-              'dependencies': [
-                # Always use GTK on Linux, even for Aura builds.
-                '../build/linux/system.gyp:gtk',
-              ],
-            }],
             ['OS=="linux" and linux_use_tcmalloc==1', {
               'dependencies': [
                 '../base/allocator/allocator.gyp:allocator',
               ],
             }],
-            ['OS=="win"', {
-              'msvs_settings': {
-                'VCManifestTool': {
-                  'EmbedManifest': 'true',
-                  'AdditionalManifestFiles': [
-                    'host/win/common-controls.manifest',
-                  ],
-                },
-                'VCLinkerTool': {
-                  'AdditionalDependencies': [
-                    'comctl32.lib',
-                  ],
-                },
-              },
-            }],
           ],
         },  # end of target 'remoting_it2me_native_messaging_host'
 
diff --git a/remoting/remoting_webapp_files.gypi b/remoting/remoting_webapp_files.gypi
index e902740..78d4998 100644
--- a/remoting/remoting_webapp_files.gypi
+++ b/remoting/remoting_webapp_files.gypi
@@ -59,8 +59,6 @@
     'remoting_webapp_js_host_files': [
       'webapp/host_controller.js',
       'webapp/host_dispatcher.js',
-      'webapp/host_it2me_dispatcher.js',
-      'webapp/host_it2me_native_messaging.js',
       'webapp/host_native_messaging.js',
       'webapp/host_session.js',
     ],
diff --git a/remoting/webapp/all_js_load.gtestjs b/remoting/webapp/all_js_load.gtestjs
index 0ab7cf8..7c72946 100644
--- a/remoting/webapp/all_js_load.gtestjs
+++ b/remoting/webapp/all_js_load.gtestjs
@@ -35,8 +35,6 @@ AllJsLoadTest.prototype = {
     'host.js',
     'host_controller.js',
     'host_dispatcher.js',
-    'host_it2me_dispatcher.js',
-    'host_it2me_native_messaging.js',
     'host_list.js',
     'host_native_messaging.js',
     //'host_plugin_proto.js',  // Only used by jscompiler
diff --git a/remoting/webapp/host_controller.js b/remoting/webapp/host_controller.js
index 21485b1..96a0bb0 100644
--- a/remoting/webapp/host_controller.js
+++ b/remoting/webapp/host_controller.js
@@ -10,7 +10,7 @@ var remoting = remoting || {};
 /** @constructor */
 remoting.HostController = function() {
   /** @return {remoting.HostPlugin} */
-  var createPluginForMe2Me = function() {
+  var createNpapiPlugin = function() {
     var plugin = remoting.HostSession.createPlugin();
     /** @type {HTMLElement} @private */
     var container = document.getElementById('daemon-plugin-container');
@@ -19,7 +19,7 @@ remoting.HostController = function() {
   };
 
   /** @type {remoting.HostDispatcher} @private */
-  this.hostDispatcher_ = new remoting.HostDispatcher(createPluginForMe2Me);
+  this.hostDispatcher_ = new remoting.HostDispatcher(createNpapiPlugin);
 
   /** @param {string} version */
   var printVersion = function(version) {
diff --git a/remoting/webapp/host_it2me_dispatcher.js b/remoting/webapp/host_it2me_dispatcher.js
deleted file mode 100644
index b018db6..0000000
--- a/remoting/webapp/host_it2me_dispatcher.js
+++ /dev/null
@@ -1,136 +0,0 @@
-// 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 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.
- */
-
-'use strict';
-
-/** @suppress {duplicate} */
-var remoting = remoting || {};
-
-/**
- * @constructor
- */
-remoting.HostIt2MeDispatcher = function() {
-  /** @type {remoting.HostIt2MeNativeMessaging} @private */
-  this.nativeMessagingHost_ = new remoting.HostIt2MeNativeMessaging();
-
-  /** @type {remoting.HostPlugin} @private */
-  this.npapiHost_ = null;
-};
-
-/**
- * @param {function():remoting.HostPlugin} createPluginCallback Callback to
- *     instantiate the NPAPI plugin when NativeMessaging is determined to be
- *     unsupported.
- * @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 {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():void} onError Callback to invoke if neither the native
- *     messaging host nor the npapi plugin works.
- */
-remoting.HostIt2MeDispatcher.prototype.initAndConnect =
-    function(createPluginCallback, email, authServiceWithToken, onStateChanged,
-             onNatPolicyChanged, xmppServerAddress, xmppServerUseTls,
-             directoryBotJid, onError) {
-  var that = this;
-  function onNativeMessagingStarted() {
-    console.log('Native Messaging supported.');
-    that.nativeMessagingHost_.connect(
-        email, authServiceWithToken, onStateChanged, onNatPolicyChanged,
-        xmppServerAddress, xmppServerUseTls, directoryBotJid);
-  }
-
-  function onNativeMessagingFailed() {
-    console.log('Native Messaging unsupported, falling back to NPAPI.');
-    that.npapiHost_ = createPluginCallback();
-    // TODO(weitaosu): is there a better way to check whether NPAPI plugin is
-    // supported?
-    if (that.npapiHost_.hasOwnProperty('REQUESTED_ACCESS_CODE')) {
-      that.npapiHost_.xmppServerAddress = xmppServerAddress;
-      that.npapiHost_.xmppServerUseTls = xmppServerUseTls;
-      that.npapiHost_.directoryBotJid = directoryBotJid;
-      that.npapiHost_.onStateChanged = onStateChanged;
-      that.npapiHost_.onNatTraversalPolicyChanged = onNatTraversalPolicyChanged;
-      that.npapiHost_.logDebugInfo = logDebugInfo;
-      that.npapiHost_.localize(chrome.i18n.getMessage);
-      that.npapiHost_.connect(email, authServiceWithToken);
-    } else {
-      onError();
-    }
-  }
-
-  this.nativeMessagingHost_.initialize(
-      onNativeMessagingStarted, onNativeMessagingFailed, onError);
-};
-
-/**
- * @return {void}
- */
-remoting.HostIt2MeDispatcher.prototype.disconnect = function() {
-  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() {
-  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() {
-  if (this.npapiHost_) {
-    return this.npapiHost_.accessCodeLifetime;
-  } else {
-    return this.nativeMessagingHost_.getAccessCodeLifetime();
-  }
-};
-
-/**
- * @return {string} The client's email address.
- */
-remoting.HostIt2MeDispatcher.prototype.getClient = function() {
-  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_);
-  }
-};
diff --git a/remoting/webapp/host_it2me_native_messaging.js b/remoting/webapp/host_it2me_native_messaging.js
deleted file mode 100644
index 567f2c5..0000000
--- a/remoting/webapp/host_it2me_native_messaging.js
+++ /dev/null
@@ -1,349 +0,0 @@
-// 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
- * Class to communicate with the It2me Host component via Native Messaging.
- */
-
-'use strict';
-
-/** @suppress {duplicate} */
-var remoting = remoting || {};
-
-/**
- * @constructor
- * @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.
- */
-remoting.HostIt2MeNativeMessaging = function() {
-  /**
-   * @type {number}
-   * @private
-   */
-  this.nextId_ = 0;
-
-  /**
-   * @type {?chrome.extension.Port}
-   * @private
-   */
-  this.port_ = null;
-
-  /**
-   * @type {string}
-   * @private
-   */
-  this.accessCode_ = '';
-
-  /**
-   * @type {number}
-   * @private
-   */
-  this.accessCodeLifetime_ = 0;
-
-  /**
-   * @type {string}
-   * @private
-   */
-  this.clientId_ = '';
-
-  /**
-   * @type {boolean}
-   * @private
-   */
-  this.initialized_ = false;
-
-  /**
-   * @type {function():void}
-   * @private
-   */
-  this.onHostStarted_ = function() {};
-
-  /**
-   * @type {function():void} Called if Native Messaging is not supported or the
-   *     It2Me Native Messaging host is not installed.
-   * @private
-   * */
-  this.onHostInitFailed_ = function() {};
-
-  /**
-   * @type {function():void} Called if the It2Me Native Messaging host sends a
-   *     malformed message: missing required attributes, attributes with
-   *     incorrect types, etc.
-   * @private
-   */
-  this.onError_ = function() {};
-
-  /**
-   * @type {function(remoting.HostSession.State):void}
-   * @private
-   */
-  this.onStateChanged_ = function() {};
-
-  /**
-   * @type {function(boolean):void}
-   * @private
-   */
-  this.onNatPolicyChanged_ = function() {};
-};
-
-/**
- * Sets up connection to the Native Messaging host process and exchanges
- * 'hello' messages. If Native Messaging is not supported or if the it2me
- * native messaging host is not installed, onHostInitFailed is invoked.
- * Otherwise, onHostStarted is invoked.
- *
- * @param {function():void} onHostStarted Called after successful
- *     initialization.
- * @param {function():void} onHostInitFailed Called if cannot connect to host.
- * @param {function():void} onError Called on host error after successfully
- *     connecting to the host.
- * @return {void}
- */
-remoting.HostIt2MeNativeMessaging.prototype.initialize =
-    function(onHostStarted, onHostInitFailed, onError) {
-  this.onHostStarted_ = onHostStarted;
-  this.onHostInitFailed_ = onHostInitFailed;
-  this.onError_ = onError;
-
-  try {
-    this.port_ = chrome.runtime.connectNative(
-        'com.google.chrome.remote_assistance');
-    this.port_.onMessage.addListener(this.onIncomingMessage_.bind(this));
-    this.port_.onDisconnect.addListener(this.onHostDisconnect_.bind(this));
-    this.postMessage_({type: 'hello'});
-  } catch (err) {
-    console.log('Native Messaging initialization failed: ',
-                /** @type {*} */ (err));
-    onHostInitFailed();
-    return;
-  }
-};
-
-/**
- * Attaches a new ID to the supplied message, and posts it to the Native
- * Messaging port.
- * |message| should have its 'type' field set, and any other fields set
- * depending on the message type.
- *
- * @param {{type: string}} message The message to post.
- * @return {void}
- * @private
- */
-remoting.HostIt2MeNativeMessaging.prototype.postMessage_ =
-    function(message) {
-  var id = this.nextId_++;
-  message['id'] = id;
-  this.port_.postMessage(message);
-};
-
-/**
- * Handler for incoming Native Messages.
- *
- * @param {Object} message The received message.
- * @return {void}
- * @private
- */
-remoting.HostIt2MeNativeMessaging.prototype.onIncomingMessage_ =
-    function(message) {
-  var type = message['type'];
-  if (!checkType_('type', type, 'string')) {
-    this.onError_();
-    return;
-  }
-
-  switch (type) {
-    case 'helloResponse':
-      /** @type {string} */
-      var version = message['version'];
-      if (checkType_('version', version, 'string')) {
-        console.log('Host version: ', version);
-        this.initialized_ = true;
-        // A "hello" request is sent immediately after the native messaging host
-        // is started. We can proceed to the next task once we receive the
-        // "helloReponse".
-        this.onHostStarted_();
-      } else {
-        this.onError_();
-      }
-      break;
-
-    case 'connectResponse':
-      console.log('connectResponse received');
-      // Response to the "connect" request. No action is needed until we
-      // receive the corresponding "hostStateChagned" message.
-      break;
-
-    case 'disconnectResponse':
-      console.log('disconnectResponse received');
-      // Response to the "disconnect" request. No action is needed until we
-      // receive the corresponding "hostStateChagned" message.
-      break;
-
-    case 'hostStateChanged':
-      /** @type {string} */
-      var stateString = message['state'];
-      if (!checkType_('stateString', stateString, 'string')) {
-        this.onError_();
-        break;
-      }
-
-      console.log('hostStateChanged received: ', stateString);
-
-      /** @type {remoting.HostSession.State} */
-      var state = remoting.HostSession.stateFromString(stateString);
-
-      switch (state) {
-        case remoting.HostSession.State.RECEIVED_ACCESS_CODE:
-          /** @type {string} */
-          var accessCode = message['accessCode'];
-          if (!checkType_('accessCode', accessCode, 'string')) {
-            this.onError_();
-            break;
-          }
-
-          /** @type {number} */
-          var accessCodeLifetime = message['accessCodeLifetime'];
-          if (!checkType_('accessCodeLifetime', accessCodeLifetime, 'number')) {
-            this.onError_();
-            break;
-          }
-
-          this.onReceivedAccessCode_(accessCode, accessCodeLifetime);
-          break;
-
-        case remoting.HostSession.State.CONNECTED:
-          /** @type {string} */
-          var client = message['client'];
-          if (checkType_('client', client, 'string')) {
-            this.onConnected_(client);
-          } else {
-            this.onError_();
-          }
-          break;
-      }
-      this.onStateChanged_(state);
-      break;
-
-    case 'natPolicyChanged':
-          /** @type {boolean} */
-      var natTraversalEnabled = message['natTraversalEnabled'];
-      if (checkType_('natTraversalEnabled', natTraversalEnabled, 'boolean')) {
-        this.onNatPolicyChanged_(natTraversalEnabled);
-      } else {
-        this.onError_();
-      }
-      break;
-
-    case 'error':
-      /** @type {string} */
-      var description = message['description'];
-      // Ignore the return value.
-      checkType_('description', description, 'string');
-      this.onError_();
-      break;
-
-    default:
-      console.error('Unexpected native message: ', message);
-      this.onError_();
-  }
-};
-
-/**
- * @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 {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.
- * @return {void}
- */
-remoting.HostIt2MeNativeMessaging.prototype.connect =
-    function(email, authServiceWithToken, onStateChanged, onNatPolicyChanged,
-             xmppServerAddress, xmppServerUseTls, directoryBotJid) {
-  this.onStateChanged_ = onStateChanged;
-  this.onNatPolicyChanged_ = onNatPolicyChanged;
-  this.postMessage_({
-      type: 'connect',
-      userName: email,
-      authServiceWithToken: authServiceWithToken,
-      xmppServerAddress: xmppServerAddress,
-      xmppServerUseTls: xmppServerUseTls,
-      directoryBotJid: directoryBotJid});
-};
-
-/**
- * @return {void}
- */
-remoting.HostIt2MeNativeMessaging.prototype.disconnect =
-    function() {
-  this.postMessage_({
-      type: 'disconnect'});
-};
-
-/**
- * @param {string} accessCode
- * @param {number} accessCodeLifetime
- * @return {void}
- * @private
- */
-remoting.HostIt2MeNativeMessaging.prototype.onReceivedAccessCode_ =
-    function(accessCode, accessCodeLifetime) {
-  this.accessCode_ = accessCode;
-  this.accessCodeLifetime_ = accessCodeLifetime;
-};
-
-/**
- * @param {string} clientId
- * @return {void}
- * @private
- */
-remoting.HostIt2MeNativeMessaging.prototype.onConnected_ =
-    function(clientId) {
-  this.clientId_ = clientId;
-};
-
-/**
- * @return {void}
- * @private
- */
-remoting.HostIt2MeNativeMessaging.prototype.onHostDisconnect_ = function() {
-  if (!this.initialized_) {
-    console.error('Native Messaging initialization failed.');
-    this.onHostInitFailed_();
-  } else {
-    console.error('Native Messaging port disconnected.');
-    this.onError_();
-  }
-}
-
-/**
- * @return {string}
- */
-remoting.HostIt2MeNativeMessaging.prototype.getAccessCode = function() {
-  return this.accessCode_
-};
-
-/**
- * @return {number}
- */
-remoting.HostIt2MeNativeMessaging.prototype.getAccessCodeLifetime = function() {
-  return this.accessCodeLifetime_
-};
-
-/**
- * @return {string}
- */
-remoting.HostIt2MeNativeMessaging.prototype.getClient = function() {
-  return this.clientId_;
-};
diff --git a/remoting/webapp/host_screen.js b/remoting/webapp/host_screen.js
index 39eb0c4..df4008b 100644
--- a/remoting/webapp/host_screen.js
+++ b/remoting/webapp/host_screen.js
@@ -14,7 +14,8 @@ var remoting = remoting || {};
 
 /**
  * @type {boolean} Whether or not the last share was cancelled by the user.
- *     This controls what screen is shown when the host signals completion.
+ *     This controls what screen is shown when the host plugin signals
+ *     completion.
  * @private
  */
 var lastShareWasCancelled_ = false;
@@ -41,38 +42,31 @@ remoting.tryShareWithToken_ = function(token) {
   disableTimeoutCountdown_();
 
   var div = document.getElementById('host-plugin-container');
-  // TODO(weitaosu): Unlike the npapi plugin, the it2me native messaging host
-  // can be long-lived and will create an it2me host on demand.  We should also
-  // keep the HostSession and HostIt2MeDispatcher object alive to avoid repeated
-  // creation of the native messaging host.
   remoting.hostSession = new remoting.HostSession();
-  remoting.hostSession.createDispatcherAndConnect(
+  remoting.hostSession.createPluginAndConnect(
       document.getElementById('host-plugin-container'),
       /** @type {string} */(remoting.identity.getCachedEmail()),
       token,
-      onHostStateChanged_,
       onNatTraversalPolicyChanged_,
-      logDebugInfo_,
-      it2meConnectFailed_);
+      onHostStateChanged_,
+      logDebugInfo_);
 };
 
 /**
  * Callback for the host plugin to notify the web app of state changes.
  * @param {remoting.HostSession.State} state The new state of the plugin.
- * @return {void} Nothing.
- * @private
  */
 function onHostStateChanged_(state) {
   if (state == remoting.HostSession.State.STARTING) {
     // Nothing to do here.
-    console.log('Host state: STARTING');
+    console.log('Host plugin state: STARTING');
 
   } else if (state == remoting.HostSession.State.REQUESTED_ACCESS_CODE) {
     // Nothing to do here.
-    console.log('Host state: REQUESTED_ACCESS_CODE');
+    console.log('Host plugin state: REQUESTED_ACCESS_CODE');
 
   } else if (state == remoting.HostSession.State.RECEIVED_ACCESS_CODE) {
-    console.log('Host state: RECEIVED_ACCESS_CODE');
+    console.log('Host plugin state: RECEIVED_ACCESS_CODE');
     var accessCode = remoting.hostSession.getAccessCode();
     var accessCodeDisplay = document.getElementById('access-code-display');
     accessCodeDisplay.innerText = '';
@@ -86,7 +80,8 @@ function onHostStateChanged_(state) {
     }
     accessCodeExpiresIn_ = remoting.hostSession.getAccessCodeLifetime();
     if (accessCodeExpiresIn_ > 0) {  // Check it hasn't expired.
-      accessCodeTimerId_ = setInterval(decrementAccessCodeTimeout_, 1000);
+      accessCodeTimerId_ = setInterval(
+          remoting.decrementAccessCodeTimeout_, 1000);
       timerRunning_ = true;
       updateAccessCodeTimeoutElement_();
       updateTimeoutStyles_();
@@ -99,7 +94,7 @@ function onHostStateChanged_(state) {
     }
 
   } else if (state == remoting.HostSession.State.CONNECTED) {
-    console.log('Host state: CONNECTED');
+    console.log('Host plugin state: CONNECTED');
     var element = document.getElementById('host-shared-message');
     var client = remoting.hostSession.getClient();
     l10n.localizeElement(element, client);
@@ -107,10 +102,10 @@ function onHostStateChanged_(state) {
     disableTimeoutCountdown_();
 
   } else if (state == remoting.HostSession.State.DISCONNECTING) {
-    console.log('Host state: DISCONNECTING');
+    console.log('Host plugin state: DISCONNECTING');
 
   } else if (state == remoting.HostSession.State.DISCONNECTED) {
-    console.log('Host state: DISCONNECTED');
+    console.log('Host plugin state: DISCONNECTED');
     if (remoting.currentMode != remoting.AppMode.HOST_SHARE_FAILED) {
       // If an error is being displayed, then the plugin should not be able to
       // hide it by setting the state. Errors must be dismissed by the user
@@ -121,13 +116,13 @@ function onHostStateChanged_(state) {
         remoting.setMode(remoting.AppMode.HOST_SHARE_FINISHED);
       }
     }
-    remoting.hostSession.cleanup();
+    remoting.hostSession.removePlugin();
 
   } else if (state == remoting.HostSession.State.ERROR) {
-    console.error('Host state: ERROR');
+    console.error('Host plugin state: ERROR');
     showShareError_(remoting.Error.UNEXPECTED);
   } else if (state == remoting.HostSession.State.INVALID_DOMAIN_ERROR) {
-    console.error('Host state: INVALID_DOMAIN_ERROR');
+    console.error('Host plugin state: INVALID_DOMAIN_ERROR');
     showShareError_(remoting.Error.INVALID_HOST_DOMAIN);
   } else {
     console.error('Unknown state -> ' + state);
@@ -138,7 +133,6 @@ function onHostStateChanged_(state) {
  * This is the callback that the host plugin invokes to indicate that there
  * is additional debug log info to display.
  * @param {string} msg The message (which will not be localized) to be logged.
- * @private
  */
 function logDebugInfo_(msg) {
   console.log('plugin: ' + msg);
@@ -149,7 +143,6 @@ function logDebugInfo_(msg) {
  *
  * @param {string} errorTag The error message to be localized and displayed.
  * @return {void} Nothing.
- * @private
  */
 function showShareError_(errorTag) {
   var errorDiv = document.getElementById('host-plugin-error');
@@ -159,21 +152,7 @@ function showShareError_(errorTag) {
 }
 
 /**
- * Show a sharing error with error code UNEXPECTED .
- *
- * @return {void} Nothing.
- * @private
- */
-function it2meConnectFailed_() {
-  // TODO (weitaosu): Instruct the user to install the native messaging host.
-  // We probably want to add a new error code (with the corresponding error
-  // message for sharing error.
-  console.error('Cannot share desktop.');
-  showShareError_(remoting.Error.UNEXPECTED);
-}
-
-/**
- * Cancel an active or pending it2me share operation.
+ * Cancel an active or pending share operation.
  *
  * @return {void} Nothing.
  */
@@ -187,7 +166,7 @@ remoting.cancelShare = function() {
     // Hack to force JSCompiler type-safety.
     var errorTyped = /** @type {{description: string}} */ error;
     console.error('Error disconnecting: ' + errorTyped.description +
-                  '. The host probably crashed.');
+                '. The host plugin probably crashed.');
     // TODO(jamiewalch): Clean this up. We should have a class representing
     // the host plugin, like we do for the client, which should handle crash
     // reporting and it should use a more detailed error message than the
@@ -216,19 +195,17 @@ var accessCodeTimerId_ = 0;
 var accessCodeExpiresIn_ = 0;
 
 /**
- * The timer callback function
- * @return {void} Nothing.
+ * The timer callback function, which needs to be visible from the global
+ * namespace.
  * @private
  */
-function decrementAccessCodeTimeout_() {
+remoting.decrementAccessCodeTimeout_ = function() {
   --accessCodeExpiresIn_;
   updateAccessCodeTimeoutElement_();
 };
 
 /**
  * Stop the access code timeout countdown if it is running.
- * @return {void} Nothing.
- * @private
  */
 function disableTimeoutCountdown_() {
   if (timerRunning_) {
@@ -251,7 +228,6 @@ var ACCESS_CODE_RED_THRESHOLD_ = 10;
  *
  * @return {boolean} True if the timeout is in progress, false if it has
  * expired.
- * @private
  */
 function updateTimeoutStyles_() {
   if (timerRunning_) {
@@ -275,8 +251,6 @@ function updateTimeoutStyles_() {
 /**
  * Update the text and appearance of the access code timeout element to
  * reflect the time remaining.
- * @return {void} Nothing.
- * @private
  */
 function updateAccessCodeTimeoutElement_() {
   var pad = (accessCodeExpiresIn_ < 10) ? '0:0' : '0:';
@@ -291,7 +265,6 @@ function updateAccessCodeTimeoutElement_() {
  * Callback to show or hide the NAT traversal warning when the policy changes.
  * @param {boolean} enabled True if NAT traversal is enabled.
  * @return {void} Nothing.
- * @private
  */
 function onNatTraversalPolicyChanged_(enabled) {
   var natBox = document.getElementById('nat-box');
diff --git a/remoting/webapp/host_session.js b/remoting/webapp/host_session.js
index a2524ee..72007a3 100644
--- a/remoting/webapp/host_session.js
+++ b/remoting/webapp/host_session.js
@@ -20,10 +20,11 @@ var remoting = remoting || {};
  * @constructor
  */
 remoting.HostSession = function() {
-  /** @type {remoting.HostIt2MeDispatcher} @private */
-  this.hostDispatcher_ = null;
 };
 
+/** @type {remoting.HostPlugin} */
+remoting.HostSession.prototype.plugin = null;
+
 // Note that these values are copied directly from host_script_object.h and
 // must be kept in sync.
 /** @enum {number} */
@@ -40,19 +41,6 @@ remoting.HostSession.State = {
 };
 
 /**
- * @param {string} stateString The string representation of the host state.
- * @return {remoting.HostSession.State} The HostSession.State enum value
- *     corresponding to stateString.
- */
-remoting.HostSession.stateFromString = function(stateString) {
-  if (!remoting.HostSession.State.hasOwnProperty(stateString)) {
-    console.error('NativeMessaging: unexpected state string: ', stateString);
-    return remoting.HostSession.State.UNKNOWN;
-  }
-  return remoting.HostSession.State[stateString];
-}
-
-/**
  * Create an instance of the host plugin.
  * @return {remoting.HostPlugin} The new plugin instance.
  */
@@ -66,59 +54,48 @@ remoting.HostSession.createPlugin = function() {
 };
 
 /**
- * Create the host dispatcher and initiate a connection.
+ * Create the host plugin and initiate a connection.
  * @param {Element} container The parent element to which to add the plugin.
  * @param {string} email The user's email address.
  * @param {string} accessToken A valid OAuth2 access token.
- * @param {function(remoting.HostSession.State):void} onStateChanged
- *     Callback for notifications of changes to the host plugin's state.
  * @param {function(boolean):void} onNatTraversalPolicyChanged Callback
  *     for notification of changes to the NAT traversal policy.
+ * @param {function(remoting.HostSession.State):void} onStateChanged
+ *     Callback for notifications of changes to the host plugin's state.
  * @param {function(string):void} logDebugInfo Callback allowing the plugin
  *     to log messages to the debug log.
- * @param {function():void} onError Callback to invoke if neither the native
- *     messaging host nor the npapi plugin works.
- * @return {void} Nothing.
  */
-remoting.HostSession.prototype.createDispatcherAndConnect =
-    function(container, email, accessToken, onStateChanged,
-             onNatTraversalPolicyChanged, logDebugInfo, onError) {
-  /** @type {remoting.HostIt2MeDispatcher} @private */
-  this.hostDispatcher_ = new remoting.HostIt2MeDispatcher();
-
-  /** @return {remoting.HostPlugin} */
-  var createPluginForIt2Me = function() {
-    var plugin = remoting.HostSession.createPlugin();
-    container.appendChild(plugin);
-    return plugin;
-  };
-
-  this.hostDispatcher_.initAndConnect(
-      createPluginForIt2Me,
-      email, 'oauth2:' + accessToken,
-      onStateChanged, onNatTraversalPolicyChanged,
-      remoting.settings.XMPP_SERVER_ADDRESS,
-      remoting.settings.XMPP_SERVER_USE_TLS,
-      remoting.settings.DIRECTORY_BOT_JID,
-      onError);
+remoting.HostSession.prototype.createPluginAndConnect =
+    function(container, email, accessToken,
+             onNatTraversalPolicyChanged, onStateChanged, logDebugInfo) {
+  this.plugin = remoting.HostSession.createPlugin();
+  container.appendChild(this.plugin);
+  this.plugin.onNatTraversalPolicyChanged = onNatTraversalPolicyChanged;
+  this.plugin.onStateChanged = onStateChanged;
+  this.plugin.logDebugInfo = logDebugInfo;
+  this.plugin.localize(chrome.i18n.getMessage);
+  this.plugin.xmppServerAddress = remoting.settings.XMPP_SERVER_ADDRESS;
+  this.plugin.xmppServerUseTls = remoting.settings.XMPP_SERVER_USE_TLS;
+  this.plugin.directoryBotJid = remoting.settings.DIRECTORY_BOT_JID;
+  this.plugin.connect(email, 'oauth2:' + accessToken);
 };
 
 /**
- * Get the access code generated by the it2me host. Valid only after the
- * host state is RECEIVED_ACCESS_CODE.
+ * Get the access code generated by the host plugin. Valid only after the
+ * plugin state is RECEIVED_ACCESS_CODE.
  * @return {string} The access code.
  */
 remoting.HostSession.prototype.getAccessCode = function() {
-  return this.hostDispatcher_.getAccessCode();
+  return this.plugin.accessCode;
 };
 
 /**
- * Get the lifetime for the access code. Valid only after the host state is
+ * Get the lifetime for the access code. Valid only after the plugin state is
  * RECEIVED_ACCESS_CODE.
  * @return {number} The access code lifetime, in seconds.
  */
 remoting.HostSession.prototype.getAccessCodeLifetime = function() {
-  return this.hostDispatcher_.getAccessCodeLifetime();
+  return this.plugin.accessCodeLifetime;
 };
 
 /**
@@ -127,21 +104,22 @@ remoting.HostSession.prototype.getAccessCodeLifetime = function() {
  * @return {string} The client's email address.
  */
 remoting.HostSession.prototype.getClient = function() {
-  return this.hostDispatcher_.getClient();
+  return this.plugin.client;
 };
 
 /**
- * Disconnect the it2me session.
+ * Disconnect the client.
  * @return {void} Nothing.
  */
 remoting.HostSession.prototype.disconnect = function() {
-  this.hostDispatcher_.disconnect();
+  this.plugin.disconnect();
 };
 
 
 /**
+ * Remove the plugin element from the document.
  * @return {void} Nothing.
  */
-remoting.HostSession.prototype.cleanup = function() {
-  this.hostDispatcher_.cleanup();
+remoting.HostSession.prototype.removePlugin = function() {
+  this.plugin.parentNode.removeChild(this.plugin);
 };
diff --git a/remoting/webapp/main.html b/remoting/webapp/main.html
index 4d2bb42..eedde24 100644
--- a/remoting/webapp/main.html
+++ b/remoting/webapp/main.html
@@ -26,8 +26,6 @@ found in the LICENSE file.
     <script src="host.js"></script>
     <script src="host_controller.js"></script>
     <script src="host_dispatcher.js"></script>
-    <script src="host_it2me_dispatcher.js"></script>
-    <script src="host_it2me_native_messaging.js"></script>
     <script src="host_list.js"></script>
     <script src="host_native_messaging.js"></script>
     <script src="host_screen.js"></script>
diff --git a/remoting/webapp/remoting.js b/remoting/webapp/remoting.js
index b0519c2..c393ab1 100644
--- a/remoting/webapp/remoting.js
+++ b/remoting/webapp/remoting.js
@@ -141,16 +141,6 @@ remoting.init = function() {
 };
 
 /**
- * Returns whether or not IT2Me is supported via the host NPAPI plugin.
- *
- * @return {boolean}
- */
-function isIT2MeSupported_() {
-  // Currently, IT2Me on Chromebooks is not supported.
-  return !remoting.runningOnChromeOS();
-}
-
-/**
  * Display the user's email address and allow access to the rest of the app,
  * including parsing URL parameters.
  *
@@ -164,6 +154,21 @@ remoting.onEmail = function(email) {
 };
 
 /**
+ * Returns whether or not IT2Me is supported via the host NPAPI plugin.
+ *
+ * @return {boolean}
+ */
+function isIT2MeSupported_() {
+  var container = document.getElementById('host-plugin-container');
+  /** @type {remoting.HostPlugin} */
+  var plugin = remoting.HostSession.createPlugin();
+  container.appendChild(plugin);
+  var result = plugin.hasOwnProperty('REQUESTED_ACCESS_CODE');
+  container.removeChild(plugin);
+  return result;
+}
+
+/**
  * initHomeScreenUi is called if the app is not starting up in session mode,
  * and also if the user cancels pin entry or the connection in session mode.
  */