Remove 'writable:false' from webview.request's definition since false is

chrome/test/data/extensions/platform_apps/web_view/shim/main.js

 // Copyright (c) 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.
 
 var util = {};
 var embedder = {};
 embedder.baseGuestURL = '';
 embedder.emptyGuestURL = '';
 embedder.windowOpenGuestURL = '';
 embedder.noReferrerGuestURL = '';
@@ skipping 368 matching lines @@
       embedder.test.assertEq(
           'function',
           typeof webview.request[apiPropertiesToCheck[i]].addRules);
       embedder.test.assertEq(
           'function',
           typeof webview.request[apiPropertiesToCheck[i]].getRules);
       embedder.test.assertEq(
           'function',
           typeof webview.request[apiPropertiesToCheck[i]].removeRules);
     }
+
+    // Try to overwrite webview.request, shall not succeed.
+    webview.request = '123';
+    embedder.test.assertTrue(typeof webview.request !== 'string');
+
     embedder.test.succeed();
   });
   webview.setAttribute('src', 'data:text/html,webview check api');
   document.body.appendChild(webview);
 }
 
 // This test verifies that the loadstart, loadstop, and exit events fire as
 // expected.
 function testEventName() {
   var webview = document.createElement('webview');
@@ skipping 1114 matching lines @@
   'testFindAPI': testFindAPI,
   'testFindAPI_findupdate': testFindAPI
 };
 
 onload = function() {
   chrome.test.getConfig(function(config) {
     embedder.setUp_(config);
     chrome.test.sendMessage("Launched");
   });
 };