[Web] Add u2f api from bitwardens repository to skip u2f when it is browser-provided

data/web/js/u2f-api.js

@@ -4,69 +4,93 @@
 //license that can be found in the LICENSE file or at
 //https://developers.google.com/open-source/licenses/bsd
 
+// ref: https://github.com/google/u2f-ref-code/blob/master/u2f-gae-demo/war/js/u2f-api.js
+
 /**
  * @fileoverview The U2F api.
  */
 'use strict';
 
-
 /**
+ * Modification:
+ * Wrap implementation so that we can exit if window.u2f is already supplied by the browser (see below).
+ */
+(function (root) {
+    /**
+     * Modification:
+     * Only continue load this library if window.u2f is not already supplied by the browser.
+     */
+    var isFirefox = navigator.userAgent.indexOf('Firefox') !== -1 || navigator.userAgent.indexOf('Gecko/') !== -1;
+    var browserImplementsU2f = !!((typeof root.u2f !== 'undefined') && root.u2f.register);
+
+    if (isFirefox && browserImplementsU2f) {
+        root.u2f.isSupported = true;
+        return;
+    }
+
+    /**
      * Namespace for the U2F api.
      * @type {Object}
      */
-var u2f = u2f || {};
+    var u2f = root.u2f || {};
 
-/**
+    /**
+     * Modification:
+     * Check if browser supports U2F API before this wrapper was added.
+     */
+    u2f.isSupported = !!(((typeof u2f !== 'undefined') && u2f.register) || ((typeof chrome !== 'undefined') && chrome.runtime));
+
+    /**
      * FIDO U2F Javascript API Version
      * @number
      */
-var js_api_version;
+    var js_api_version;
 
-/**
+    /**
      * The U2F extension id
      * @const {string}
      */
-// The Chrome packaged app extension ID.
+    // The Chrome packaged app extension ID.
-// Uncomment this if you want to deploy a server instance that uses
+    // Uncomment this if you want to deploy a server instance that uses
-// the package Chrome app and does not require installing the U2F Chrome extension.
+    // the package Chrome app and does not require installing the U2F Chrome extension.
     u2f.EXTENSION_ID = 'kmendfapggjehodndflmmgagdbamhnfd';
-// The U2F Chrome extension ID.
+    // The U2F Chrome extension ID.
-// Uncomment this if you want to deploy a server instance that uses
+    // Uncomment this if you want to deploy a server instance that uses
-// the U2F Chrome extension to authenticate.
+    // the U2F Chrome extension to authenticate.
-// u2f.EXTENSION_ID = 'pfboblefjcgdjicmnffhdgionmgcdmne';
+    // u2f.EXTENSION_ID = 'pfboblefjcgdjicmnffhdgionmgcdmne';
 
 
-/**
+    /**
      * Message types for messsages to/from the extension
      * @const
      * @enum {string}
      */
-u2f.MessageTypes = {
+    u2f.MessageTypes = {
         'U2F_REGISTER_REQUEST': 'u2f_register_request',
         'U2F_REGISTER_RESPONSE': 'u2f_register_response',
         'U2F_SIGN_REQUEST': 'u2f_sign_request',
         'U2F_SIGN_RESPONSE': 'u2f_sign_response',
         'U2F_GET_API_VERSION_REQUEST': 'u2f_get_api_version_request',
         'U2F_GET_API_VERSION_RESPONSE': 'u2f_get_api_version_response'
-};
+    };
 
 
-/**
+    /**
      * Response status codes
      * @const
      * @enum {number}
      */
-u2f.ErrorCodes = {
+    u2f.ErrorCodes = {
         'OK': 0,
         'OTHER_ERROR': 1,
         'BAD_REQUEST': 2,
         'CONFIGURATION_UNSUPPORTED': 3,
         'DEVICE_INELIGIBLE': 4,
         'TIMEOUT': 5
-};
+    };
 
 
-/**
+    /**
      * A message for registration requests
      * @typedef {{
      *   type: u2f.MessageTypes,
@@ -75,10 +99,10 @@ u2f.ErrorCodes = {
      *   requestId: ?number
      * }}
      */
-u2f.U2fRequest;
+    u2f.U2fRequest;
 
 
-/**
+    /**
      * A message for registration responses
      * @typedef {{
      *   type: u2f.MessageTypes,
@@ -86,32 +110,32 @@ u2f.U2fRequest;
      *   requestId: ?number
      * }}
      */
-u2f.U2fResponse;
+    u2f.U2fResponse;
 
 
-/**
+    /**
      * An error object for responses
      * @typedef {{
      *   errorCode: u2f.ErrorCodes,
      *   errorMessage: ?string
      * }}
      */
-u2f.Error;
+    u2f.Error;
 
-/**
+    /**
      * Data object for a single sign request.
      * @typedef {enum {BLUETOOTH_RADIO, BLUETOOTH_LOW_ENERGY, USB, NFC}}
      */
-u2f.Transport;
+    u2f.Transport;
 
 
-/**
+    /**
      * Data object for a single sign request.
      * @typedef {Array<u2f.Transport>}
      */
-u2f.Transports;
+    u2f.Transports;
 
-/**
+    /**
      * Data object for a single sign request.
      * @typedef {{
      *   version: string,
@@ -120,10 +144,10 @@ u2f.Transports;
      *   appId: string
      * }}
      */
-u2f.SignRequest;
+    u2f.SignRequest;
 
 
-/**
+    /**
      * Data object for a sign response.
      * @typedef {{
      *   keyHandle: string,
@@ -131,20 +155,20 @@ u2f.SignRequest;
      *   clientData: string
      * }}
      */
-u2f.SignResponse;
+    u2f.SignResponse;
 
 
-/**
+    /**
      * Data object for a registration request.
      * @typedef {{
      *   version: string,
      *   challenge: string
      * }}
      */
-u2f.RegisterRequest;
+    u2f.RegisterRequest;
 
 
-/**
+    /**
      * Data object for a registration response.
      * @typedef {{
      *   version: string,
@@ -153,10 +177,10 @@ u2f.RegisterRequest;
      *   appId: string
      * }}
      */
-u2f.RegisterResponse;
+    u2f.RegisterResponse;
 
 
-/**
+    /**
      * Data object for a registered key.
      * @typedef {{
      *   version: string,
@@ -165,26 +189,26 @@ u2f.RegisterResponse;
      *   appId: ?string
      * }}
      */
-u2f.RegisteredKey;
+    u2f.RegisteredKey;
 
 
-/**
+    /**
      * Data object for a get API register response.
      * @typedef {{
      *   js_api_version: number
      * }}
      */
-u2f.GetJsApiVersionResponse;
+    u2f.GetJsApiVersionResponse;
 
 
-//Low level MessagePort API support
+    //Low level MessagePort API support
 
-/**
+    /**
      * Sets up a MessagePort to the U2F extension using the
      * available mechanisms.
      * @param {function((MessagePort|u2f.WrappedChromeRuntimePort_))} callback
      */
-u2f.getMessagePort = function(callback) {
+    u2f.getMessagePort = function (callback) {
         if (typeof chrome != 'undefined' && chrome.runtime) {
             // The actual message here does not matter, but we need to get a reply
             // for the callback to run. Thus, send an empty signature request
@@ -193,7 +217,7 @@ u2f.getMessagePort = function(callback) {
                 type: u2f.MessageTypes.U2F_SIGN_REQUEST,
                 signRequests: []
             };
-    chrome.runtime.sendMessage(u2f.EXTENSION_ID, msg, function() {
+            chrome.runtime.sendMessage(u2f.EXTENSION_ID, msg, function () {
                 if (!chrome.runtime.lastError) {
                     // We are on a whitelisted origin and can talk directly
                     // with the extension.
@@ -213,80 +237,80 @@ u2f.getMessagePort = function(callback) {
             // when this origin doesn't have access to any extensions.
             u2f.getIframePort_(callback);
         }
-};
+    };
 
-/**
+    /**
      * Detect chrome running on android based on the browser's useragent.
      * @private
      */
-u2f.isAndroidChrome_ = function() {
+    u2f.isAndroidChrome_ = function () {
         var userAgent = navigator.userAgent;
         return userAgent.indexOf('Chrome') != -1 &&
             userAgent.indexOf('Android') != -1;
-};
+    };
 
-/**
+    /**
      * Detect chrome running on iOS based on the browser's platform.
      * @private
      */
-u2f.isIosChrome_ = function() {
+    u2f.isIosChrome_ = function () {
         return ["iPhone", "iPad", "iPod"].indexOf(navigator.platform) > -1;
-};
+    };
 
-/**
+    /**
      * Connects directly to the extension via chrome.runtime.connect.
      * @param {function(u2f.WrappedChromeRuntimePort_)} callback
      * @private
      */
-u2f.getChromeRuntimePort_ = function(callback) {
+    u2f.getChromeRuntimePort_ = function (callback) {
         var port = chrome.runtime.connect(u2f.EXTENSION_ID,
-      {'includeTlsChannelId': true});
+            { 'includeTlsChannelId': true });
-  setTimeout(function() {
+        setTimeout(function () {
             callback(new u2f.WrappedChromeRuntimePort_(port));
         }, 0);
-};
+    };
 
-/**
+    /**
      * Return a 'port' abstraction to the Authenticator app.
      * @param {function(u2f.WrappedAuthenticatorPort_)} callback
      * @private
      */
-u2f.getAuthenticatorPort_ = function(callback) {
+    u2f.getAuthenticatorPort_ = function (callback) {
-  setTimeout(function() {
+        setTimeout(function () {
             callback(new u2f.WrappedAuthenticatorPort_());
         }, 0);
-};
+    };
 
-/**
+    /**
      * Return a 'port' abstraction to the iOS client app.
      * @param {function(u2f.WrappedIosPort_)} callback
      * @private
      */
-u2f.getIosPort_ = function(callback) {
+    u2f.getIosPort_ = function (callback) {
-  setTimeout(function() {
+        setTimeout(function () {
             callback(new u2f.WrappedIosPort_());
         }, 0);
-};
+    };
 
-/**
+    /**
      * A wrapper for chrome.runtime.Port that is compatible with MessagePort.
      * @param {Port} port
      * @constructor
      * @private
      */
-u2f.WrappedChromeRuntimePort_ = function(port) {
+    u2f.WrappedChromeRuntimePort_ = function (port) {
         this.port_ = port;
-};
+    };
 
-/**
+    /**
      * Format and return a sign request compliant with the JS API version supported by the extension.
      * @param {Array<u2f.SignRequest>} signRequests
      * @param {number} timeoutSeconds
      * @param {number} reqId
      * @return {Object}
      */
-u2f.formatSignRequest_ =
+    u2f.formatSignRequest_ =
-  function(appId, challenge, registeredKeys, timeoutSeconds, reqId) {
+        function (appId, challenge, registeredKeys, timeoutSeconds, reqId) {
             if (js_api_version === undefined || js_api_version < 1.1) {
                 // Adapt request to the 1.0 JS API
                 var signRequests = [];
@@ -314,9 +338,9 @@ u2f.formatSignRequest_ =
                 timeoutSeconds: timeoutSeconds,
                 requestId: reqId
             };
-};
+        };
 
-/**
+    /**
      * Format and return a register request compliant with the JS API version supported by the extension..
      * @param {Array<u2f.SignRequest>} signRequests
      * @param {Array<u2f.RegisterRequest>} signRequests
@@ -324,8 +348,8 @@ u2f.formatSignRequest_ =
      * @param {number} reqId
      * @return {Object}
      */
-u2f.formatRegisterRequest_ =
+    u2f.formatRegisterRequest_ =
-  function(appId, registeredKeys, registerRequests, timeoutSeconds, reqId) {
+        function (appId, registeredKeys, registerRequests, timeoutSeconds, reqId) {
             if (js_api_version === undefined || js_api_version < 1.1) {
                 // Adapt request to the 1.0 JS API
                 for (var i = 0; i < registerRequests.length; i++) {
@@ -357,74 +381,74 @@ u2f.formatRegisterRequest_ =
                 timeoutSeconds: timeoutSeconds,
                 requestId: reqId
             };
-};
+        };
 
 
-/**
+    /**
      * Posts a message on the underlying channel.
      * @param {Object} message
      */
-u2f.WrappedChromeRuntimePort_.prototype.postMessage = function(message) {
+    u2f.WrappedChromeRuntimePort_.prototype.postMessage = function (message) {
         this.port_.postMessage(message);
-};
+    };
 
 
-/**
+    /**
      * Emulates the HTML 5 addEventListener interface. Works only for the
      * onmessage event, which is hooked up to the chrome.runtime.Port.onMessage.
      * @param {string} eventName
      * @param {function({data: Object})} handler
      */
-u2f.WrappedChromeRuntimePort_.prototype.addEventListener =
+    u2f.WrappedChromeRuntimePort_.prototype.addEventListener =
-    function(eventName, handler) {
+        function (eventName, handler) {
             var name = eventName.toLowerCase();
             if (name == 'message' || name == 'onmessage') {
-    this.port_.onMessage.addListener(function(message) {
+                this.port_.onMessage.addListener(function (message) {
                     // Emulate a minimal MessageEvent object
-      handler({'data': message});
+                    handler({ 'data': message });
                 });
             } else {
                 console.error('WrappedChromeRuntimePort only supports onMessage');
             }
-};
+        };
 
-/**
+    /**
      * Wrap the Authenticator app with a MessagePort interface.
      * @constructor
      * @private
      */
-u2f.WrappedAuthenticatorPort_ = function() {
+    u2f.WrappedAuthenticatorPort_ = function () {
         this.requestId_ = -1;
         this.requestObject_ = null;
-}
+    }
 
-/**
+    /**
      * Launch the Authenticator intent.
      * @param {Object} message
      */
-u2f.WrappedAuthenticatorPort_.prototype.postMessage = function(message) {
+    u2f.WrappedAuthenticatorPort_.prototype.postMessage = function (message) {
         var intentUrl =
             u2f.WrappedAuthenticatorPort_.INTENT_URL_BASE_ +
             ';S.request=' + encodeURIComponent(JSON.stringify(message)) +
             ';end';
         document.location = intentUrl;
-};
+    };
 
-/**
+    /**
      * Tells what type of port this is.
      * @return {String} port type
      */
-u2f.WrappedAuthenticatorPort_.prototype.getPortType = function() {
+    u2f.WrappedAuthenticatorPort_.prototype.getPortType = function () {
         return "WrappedAuthenticatorPort_";
-};
+    };
 
 
-/**
+    /**
      * Emulates the HTML 5 addEventListener interface.
      * @param {string} eventName
      * @param {function({data: Object})} handler
      */
-u2f.WrappedAuthenticatorPort_.prototype.addEventListener = function(eventName, handler) {
+    u2f.WrappedAuthenticatorPort_.prototype.addEventListener = function (eventName, handler) {
         var name = eventName.toLowerCase();
         if (name == 'message') {
             var self = this;
@@ -435,15 +459,15 @@ u2f.WrappedAuthenticatorPort_.prototype.addEventListener = function(eventName, h
         } else {
             console.error('WrappedAuthenticatorPort only supports message');
         }
-};
+    };
 
-/**
+    /**
      * Callback invoked  when a response is received from the Authenticator.
      * @param function({data: Object}) callback
      * @param {Object} message message Object
      */
-u2f.WrappedAuthenticatorPort_.prototype.onRequestUpdate_ =
+    u2f.WrappedAuthenticatorPort_.prototype.onRequestUpdate_ =
-    function(callback, message) {
+        function (callback, message) {
             var messageObject = JSON.parse(message.data);
             var intentUrl = messageObject['intentURL'];
 
@@ -454,60 +478,60 @@ u2f.WrappedAuthenticatorPort_.prototype.onRequestUpdate_ =
                     JSON.parse(messageObject['data']));
             }
 
-  callback({'data': responseObject});
+            callback({ 'data': responseObject });
-};
+        };
 
-/**
+    /**
      * Base URL for intents to Authenticator.
      * @const
      * @private
      */
-u2f.WrappedAuthenticatorPort_.INTENT_URL_BASE_ =
+    u2f.WrappedAuthenticatorPort_.INTENT_URL_BASE_ =
         'intent:#Intent;action=com.google.android.apps.authenticator.AUTHENTICATE';
 
-/**
+    /**
      * Wrap the iOS client app with a MessagePort interface.
      * @constructor
      * @private
      */
-u2f.WrappedIosPort_ = function() {};
+    u2f.WrappedIosPort_ = function () { };
 
-/**
+    /**
      * Launch the iOS client app request
      * @param {Object} message
      */
-u2f.WrappedIosPort_.prototype.postMessage = function(message) {
+    u2f.WrappedIosPort_.prototype.postMessage = function (message) {
         var str = JSON.stringify(message);
         var url = "u2f://auth?" + encodeURI(str);
         location.replace(url);
-};
+    };
 
-/**
+    /**
      * Tells what type of port this is.
      * @return {String} port type
      */
-u2f.WrappedIosPort_.prototype.getPortType = function() {
+    u2f.WrappedIosPort_.prototype.getPortType = function () {
         return "WrappedIosPort_";
-};
+    };
 
-/**
+    /**
      * Emulates the HTML 5 addEventListener interface.
      * @param {string} eventName
      * @param {function({data: Object})} handler
      */
-u2f.WrappedIosPort_.prototype.addEventListener = function(eventName, handler) {
+    u2f.WrappedIosPort_.prototype.addEventListener = function (eventName, handler) {
         var name = eventName.toLowerCase();
         if (name !== 'message') {
             console.error('WrappedIosPort only supports message');
         }
-};
+    };
 
-/**
+    /**
      * Sets up an embedded trampoline iframe, sourced from the extension.
      * @param {function(MessagePort)} callback
      * @private
      */
-u2f.getIframePort_ = function(callback) {
+    u2f.getIframePort_ = function (callback) {
         // Create the iframe
         var iframeOrigin = 'chrome-extension://' + u2f.EXTENSION_ID;
         var iframe = document.createElement('iframe');
@@ -516,7 +540,7 @@ u2f.getIframePort_ = function(callback) {
         document.body.appendChild(iframe);
 
         var channel = new MessageChannel();
-  var ready = function(message) {
+        var ready = function (message) {
             if (message.data == 'ready') {
                 channel.port1.removeEventListener('message', ready);
                 callback(channel.port1);
@@ -527,64 +551,64 @@ u2f.getIframePort_ = function(callback) {
         channel.port1.addEventListener('message', ready);
         channel.port1.start();
 
-  iframe.addEventListener('load', function() {
+        iframe.addEventListener('load', function () {
             // Deliver the port to the iframe and initialize
             iframe.contentWindow.postMessage('init', iframeOrigin, [channel.port2]);
         });
-};
+    };
 
 
-//High-level JS API
+    //High-level JS API
 
-/**
+    /**
      * Default extension response timeout in seconds.
      * @const
      */
-u2f.EXTENSION_TIMEOUT_SEC = 30;
+    u2f.EXTENSION_TIMEOUT_SEC = 30;
 
-/**
+    /**
      * A singleton instance for a MessagePort to the extension.
      * @type {MessagePort|u2f.WrappedChromeRuntimePort_}
      * @private
      */
-u2f.port_ = null;
+    u2f.port_ = null;
 
-/**
+    /**
      * Callbacks waiting for a port
      * @type {Array<function((MessagePort|u2f.WrappedChromeRuntimePort_))>}
      * @private
      */
-u2f.waitingForPort_ = [];
+    u2f.waitingForPort_ = [];
 
-/**
+    /**
      * A counter for requestIds.
      * @type {number}
      * @private
      */
-u2f.reqCounter_ = 0;
+    u2f.reqCounter_ = 0;
 
-/**
+    /**
      * A map from requestIds to client callbacks
      * @type {Object.<number,(function((u2f.Error|u2f.RegisterResponse))
      *                       |function((u2f.Error|u2f.SignResponse)))>}
      * @private
      */
-u2f.callbackMap_ = {};
+    u2f.callbackMap_ = {};
 
-/**
+    /**
      * Creates or retrieves the MessagePort singleton to use.
      * @param {function((MessagePort|u2f.WrappedChromeRuntimePort_))} callback
      * @private
      */
-u2f.getPortSingleton_ = function(callback) {
+    u2f.getPortSingleton_ = function (callback) {
         if (u2f.port_) {
             callback(u2f.port_);
         } else {
             if (u2f.waitingForPort_.length == 0) {
-      u2f.getMessagePort(function(port) {
+                u2f.getMessagePort(function (port) {
                     u2f.port_ = port;
                     u2f.port_.addEventListener('message',
-            /** @type {function(Event)} */ (u2f.responseHandler_));
+            /** @type {function(Event)} */(u2f.responseHandler_));
 
                     // Careful, here be async callbacks. Maybe.
                     while (u2f.waitingForPort_.length)
@@ -593,14 +617,14 @@ u2f.getPortSingleton_ = function(callback) {
             }
             u2f.waitingForPort_.push(callback);
         }
-};
+    };
 
-/**
+    /**
      * Handles response messages from the extension.
      * @param {MessageEvent.<u2f.Response>} message
      * @private
      */
-u2f.responseHandler_ = function(message) {
+    u2f.responseHandler_ = function (message) {
         var response = message.data;
         var reqId = response['requestId'];
         if (!reqId || !u2f.callbackMap_[reqId]) {
@@ -610,9 +634,9 @@ u2f.responseHandler_ = function(message) {
         var cb = u2f.callbackMap_[reqId];
         delete u2f.callbackMap_[reqId];
         cb(response['responseData']);
-};
+    };
 
-/**
+    /**
      * Dispatches an array of sign requests to available U2F tokens.
      * If the JS API version supported by the extension is unknown, it first sends a
      * message to the extension to find out the supported API version and then it sends
@@ -623,7 +647,7 @@ u2f.responseHandler_ = function(message) {
      * @param {function((u2f.Error|u2f.SignResponse))} callback
      * @param {number=} opt_timeoutSeconds
      */
-u2f.sign = function(appId, challenge, registeredKeys, callback, opt_timeoutSeconds) {
+    u2f.sign = function (appId, challenge, registeredKeys, callback, opt_timeoutSeconds) {
         if (js_api_version === undefined) {
             // Send a message to get the extension to JS API version, then send the actual sign request.
             u2f.getApiVersion(
@@ -636,9 +660,9 @@ u2f.sign = function(appId, challenge, registeredKeys, callback, opt_timeoutSecon
             // We know the JS API version. Send the actual sign request in the supported API version.
             u2f.sendSignRequest(appId, challenge, registeredKeys, callback, opt_timeoutSeconds);
         }
-};
+    };
 
-/**
+    /**
      * Dispatches an array of sign requests to available U2F tokens.
      * @param {string=} appId
      * @param {string=} challenge
@@ -646,8 +670,8 @@ u2f.sign = function(appId, challenge, registeredKeys, callback, opt_timeoutSecon
      * @param {function((u2f.Error|u2f.SignResponse))} callback
      * @param {number=} opt_timeoutSeconds
      */
-u2f.sendSignRequest = function(appId, challenge, registeredKeys, callback, opt_timeoutSeconds) {
+    u2f.sendSignRequest = function (appId, challenge, registeredKeys, callback, opt_timeoutSeconds) {
-  u2f.getPortSingleton_(function(port) {
+        u2f.getPortSingleton_(function (port) {
             var reqId = ++u2f.reqCounter_;
             u2f.callbackMap_[reqId] = callback;
             var timeoutSeconds = (typeof opt_timeoutSeconds !== 'undefined' ?
@@ -655,9 +679,9 @@ u2f.sendSignRequest = function(appId, challenge, registeredKeys, callback, opt_t
             var req = u2f.formatSignRequest_(appId, challenge, registeredKeys, timeoutSeconds, reqId);
             port.postMessage(req);
         });
-};
+    };
 
-/**
+    /**
      * Dispatches register requests to available U2F tokens. An array of sign
      * requests identifies already registered tokens.
      * If the JS API version supported by the extension is unknown, it first sends a
@@ -669,12 +693,12 @@ u2f.sendSignRequest = function(appId, challenge, registeredKeys, callback, opt_t
      * @param {function((u2f.Error|u2f.RegisterResponse))} callback
      * @param {number=} opt_timeoutSeconds
      */
-u2f.register = function(appId, registerRequests, registeredKeys, callback, opt_timeoutSeconds) {
+    u2f.register = function (appId, registerRequests, registeredKeys, callback, opt_timeoutSeconds) {
         if (js_api_version === undefined) {
             // Send a message to get the extension to JS API version, then send the actual register request.
             u2f.getApiVersion(
                 function (response) {
-          js_api_version = response['js_api_version'] === undefined ? 0: response['js_api_version'];
+                    js_api_version = response['js_api_version'] === undefined ? 0 : response['js_api_version'];
                     console.log("Extension JS API Version: ", js_api_version);
                     u2f.sendRegisterRequest(appId, registerRequests, registeredKeys,
                         callback, opt_timeoutSeconds);
@@ -684,9 +708,9 @@ u2f.register = function(appId, registerRequests, registeredKeys, callback, opt_t
             u2f.sendRegisterRequest(appId, registerRequests, registeredKeys,
                 callback, opt_timeoutSeconds);
         }
-};
+    };
 
-/**
+    /**
      * Dispatches register requests to available U2F tokens. An array of sign
      * requests identifies already registered tokens.
      * @param {string=} appId
@@ -695,8 +719,8 @@ u2f.register = function(appId, registerRequests, registeredKeys, callback, opt_t
      * @param {function((u2f.Error|u2f.RegisterResponse))} callback
      * @param {number=} opt_timeoutSeconds
      */
-u2f.sendRegisterRequest = function(appId, registerRequests, registeredKeys, callback, opt_timeoutSeconds) {
+    u2f.sendRegisterRequest = function (appId, registerRequests, registeredKeys, callback, opt_timeoutSeconds) {
-  u2f.getPortSingleton_(function(port) {
+        u2f.getPortSingleton_(function (port) {
             var reqId = ++u2f.reqCounter_;
             u2f.callbackMap_[reqId] = callback;
             var timeoutSeconds = (typeof opt_timeoutSeconds !== 'undefined' ?
@@ -705,10 +729,10 @@ u2f.sendRegisterRequest = function(appId, registerRequests, registeredKeys, call
                 appId, registeredKeys, registerRequests, timeoutSeconds, reqId);
             port.postMessage(req);
         });
-};
+    };
 
 
-/**
+    /**
      * Dispatches a message to the extension to find out the supported
      * JS API version.
      * If the user is on a mobile phone and is thus using Google Authenticator instead
@@ -716,8 +740,8 @@ u2f.sendRegisterRequest = function(appId, registerRequests, registeredKeys, call
      * @param {function((u2f.Error|u2f.GetJsApiVersionResponse))} callback
      * @param {number=} opt_timeoutSeconds
      */
-u2f.getApiVersion = function(callback, opt_timeoutSeconds) {
+    u2f.getApiVersion = function (callback, opt_timeoutSeconds) {
- u2f.getPortSingleton_(function(port) {
+        u2f.getPortSingleton_(function (port) {
             // If we are using Android Google Authenticator or iOS client app,
             // do not fire an intent to ask which JS API version to use.
             if (port.getPortType) {
@@ -745,4 +769,11 @@ u2f.getApiVersion = function(callback, opt_timeoutSeconds) {
             };
             port.postMessage(req);
         });
-};
+    };
+
+    /**
+     * Modification:
+     * Assign u2f back to window (root) scope.
+     */
+    root.u2f = u2f;
+}(this));