Enable 3rd party support for Security Keys.

chrome/browser/resources/cryptotoken/usbsignhandler.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 Implements a sign handler using USB gnubbies.
  */
 'use strict';
 
 var CORRUPT_sign = false;
@@ skipping 29 matching lines @@
  */
 UsbSignHandler.prototype.run = function(cb) {
   if (this.cb_) {
     // Can only handle one request.
     return false;
   }
   /** @private {RequestHandlerCallback} */
   this.cb_ = cb;
   if (!this.request_.signData || !this.request_.signData.length) {
     // Fail a sign request with an empty set of challenges.
-    this.notifyError_(DeviceStatusCodes.INVALID_DATA_STATUS);
     return false;
   }
   var timeoutMillis =
       this.request_.timeoutSeconds ?
       this.request_.timeoutSeconds * 1000 :
       UsbSignHandler.DEFAULT_TIMEOUT_MILLIS;
   /** @private {MultipleGnubbySigner} */
   this.signer_ = new MultipleGnubbySigner(
       false /* forEnroll */,
       this.signerCompleted_.bind(this),
@@ skipping 193 matching lines @@
 UsbSignHandler.prototype.close = function() {
   while (this.notEnrolledGnubbies_.length != 0) {
     var gnubby = this.notEnrolledGnubbies_.shift();
     gnubby.closeWhenIdle();
   }
   if (this.signer_) {
     this.signer_.close();
     this.signer_ = null;
   }
 };