Implement Web Restrictions in WebView.

components/supervised_user_error_page/resources/supervised_user_block_interstitial.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.
 
 function sendCommand(cmd) {
   window.domAutomationController.setAutomationId(1);
   window.domAutomationController.send(cmd);
 }
 
 function makeImageSet(url1x, url2x) {
   return '-webkit-image-set(url(' + url1x + ') 1x, url(' + url2x + ') 2x)';
 }
 
 function initialize() {
   if (loadTimeData.getBoolean('allowAccessRequests')) {
     $('request-access-button').onclick = function(event) {
       $('request-access-button').hidden = true;
-      sendCommand('request');
+      if (window.domAutomationController) {
+        sendCommand('request');
+      } else {
+        window.webRestrictions.requestPermission(setRequestStatus);
+      }
     };
   } else {
     $('request-access-button').hidden = true;
   }
   var avatarURL1x = loadTimeData.getString('avatarURL1x');
   var avatarURL2x = loadTimeData.getString('avatarURL2x');
   var custodianName = loadTimeData.getString('custodianName');
   if (custodianName) {
     $('custodians-information').hidden = false;
     if (avatarURL1x) {
@@ skipping 12 matching lines @@
         $('second-custodian-avatar-img').style.content =
             makeImageSet(secondAvatarURL1x, secondAvatarURL2x);
       }
       $('second-custodian-name').innerHTML = secondCustodianName;
       $('second-custodian-email').innerHTML = loadTimeData.getString(
           'secondCustodianEmail');
     }
   }
   var showDetailsLink = loadTimeData.getString('showDetailsLink');
   $('show-details-link').hidden = !showDetailsLink;
-  $('back-button').hidden = showDetailsLink;
+  $('back-button').hidden = showDetailsLink || !window.domAutomationController;
   $('back-button').onclick = function(event) {
     sendCommand('back');
   };
   $('show-details-link').onclick = function(event) {
     $('details').hidden = false;
     $('show-details-link').hidden = true;
     $('hide-details-link').hidden = false;
     $('information-container').classList.add('hidden-on-mobile');
     $('request-access-button').classList.add('hidden-on-mobile');
   };
   $('hide-details-link').onclick = function(event) {
     $('details').hidden = true;
     $('show-details-link').hidden = false;
     $('hide-details-link').hidden = true;
     $('information-container').classList.remove('hidden-on-mobile');
     $('request-access-button').classList.remove('hidden-on-mobile');
   };
-  if (loadTimeData.getBoolean('showFeedbackLink')) {
+  if (window.domAutomationController &&
+        loadTimeData.getBoolean('showFeedbackLink')) {
     $('feedback-link').onclick = function(event) {
       sendCommand('feedback');
     };
   } else {
     $('feedback').hidden = true;
   }
 }
 
 /**
  * Updates the interstitial to show that the request failed or was sent.
  * @param {boolean} isSuccessful Whether the request was successful or not.
  */
 function setRequestStatus(isSuccessful) {
+  console.log('setRequestStatus(' + isSuccessful +')');
   $('block-page-message').hidden = true;
   if (isSuccessful) {
     $('request-failed-message').hidden = true;
     $('request-sent-message').hidden = false;
     $('show-details-link').hidden = true;
     $('hide-details-link').hidden = true;
     $('details').hidden = true;
-    $('back-button').hidden = false;
+    $('back-button').hidden = !window.domAutomationController;
     $('request-access-button').hidden = true;
   } else {
     $('request-failed-message').hidden = false;
     $('request-access-button').hidden = false;
   }
 }
 
 document.addEventListener('DOMContentLoaded', initialize);