Catches and ignores errors when accessing win.document in Password Autofill JS

ios/chrome/browser/passwords/resources/password_controller.js

 // Copyright 2012 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.
 
 // This file adheres to closure-compiler conventions in order to enable
 // compilation with ADVANCED_OPTIMIZATIONS. See http://goo.gl/FwOgy
 //
 // Installs password management functions on the |__gCrWeb| object.
 //
 // Finds all password forms in the current document and extracts
@@ skipping 325 matching lines @@
 
   /**
    * Finds all forms with passwords in the supplied window or frame and appends
    * JS objects containing the form data to |formDataList|.
    * @param {!Array.<Object>} formDataList A list that this function populates
    *     with descriptions of discovered forms.
    * @param {Window} win A window (or frame) in which the function should
    *    look for password forms.
    */
   __gCrWeb.getPasswordFormDataList = function(formDataList, win) {
-    var doc = win.document;
+    var doc = null;
 
-    // We may not be allowed to read the 'document' property from a frame
-    // that is in a different domain.
+    try {
+      // Security violations may generate an exception or null to be returned.
+      doc = win.document;
+    } catch(e) {
+    }
+
     if (!doc) {
       return;
     }
 
     var forms = doc.forms;
     for (var i = 0; i < forms.length; i++) {
       var formData = __gCrWeb.getPasswordFormData(forms[i]);
       if (formData) {
         formDataList.push(formData);
       }
@@ skipping 62 matching lines @@
       'method': formElement.getAttribute('method'),
       'name': __gCrWeb.common.getFormIdentifier(formElement),
       'origin': origin,
       'fields': fields,
       'usernameElement': usernameElement,
       'usernameValue': usernameValue,
       'passwords': passwords
     };
   };
 }