Fix login navigation button enabling

chrome/browser/resources/chromeos/login/oobe_screen_oauth_enrollment.js

 // Copyright 2015 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.
 
 login.createScreen('OAuthEnrollmentScreen', 'oauth-enrollment', function() {
   /* Code which is embedded inside of the webview. See below for details.
   /** @const */ var INJECTED_WEBVIEW_SCRIPT = String.raw`
                       (function() {
                          <include src="../keyboard/keyboard_utils.js">
                          keyboard.initializeKeyboardFlow(true);
@@ skipping 117 matching lines @@
             this.updateControlsState();
           }).bind(this));
 
       this.authenticator_.addEventListener('backButton',
           (function(e) {
             this.lastBackMessageValue_ = !!e.detail;
             $('oauth-enroll-auth-view').focus();
             this.updateControlsState();
           }).bind(this));
 
+      this.authenticator_.addEventListener('dialogShown',
+        (function(e) {
+          this.navigation_.disabled = true;
+        }).bind(this));
+
+      this.authenticator_.addEventListener('dialogHidden',
+        (function(e) {
+          this.navigation_.disabled = false;
+        }).bind(this));
+
       this.authenticator_.insecureContentBlockedCallback =
           (function(url) {
             this.showError(
                 loadTimeData.getStringF('insecureURLEnrollmentError', url),
                 false);
           }).bind(this);
 
       this.authenticator_.missingGaiaInfoCallback =
           (function() {
             this.showError(
@@ skipping 79 matching lines @@
       this.authenticator_.load(cr.login.Authenticator.AuthMode.DEFAULT,
                                gaiaParams);
 
       var modes = ['manual', 'forced', 'recovery'];
       for (var i = 0; i < modes.length; ++i) {
         this.classList.toggle('mode-' + modes[i],
                               data.enrollment_mode == modes[i]);
       }
       this.isManualEnrollment_ = data.enrollment_mode === 'manual';
       this.isCancelDisabled = true;
+      this.navigation_.disabled = false;
 
       this.showStep(data.attestationBased ? STEP_WORKING : STEP_SIGNIN);
     },
 
     onBeforeHide: function() {
       $('login-header-bar').signinUIState = SIGNIN_UI_STATE.HIDDEN;
     },
 
     /**
      * Shows attribute-prompt step with pre-filled asset ID and
@@ skipping 123 matching lines @@
                                      this.lastBackMessageValue_;
       this.navigation_.refreshVisible = this.isAtTheBeginning() &&
                                         !this.isManualEnrollment_;
       this.navigation_.closeVisible = (this.currentStep_ == STEP_SIGNIN ||
                                        this.currentStep_ == STEP_ERROR) &&
                                       !this.navigation_.refreshVisible;
       $('login-header-bar').updateUI_();
     }
   };
 });