Remove command line/field trial support and configs for Isolate Extensions.

chrome/test/data/extensions/api_test/content_scripts/extension_iframe/iframe.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.
 
 // Simple success test: we want content-script APIs to be available (like
 // sendRequest), but other APIs to be undefined or throw exceptions on access.
 
 chrome.test.getConfig(function(config) {
   'use strict';
 
   let success = true;
-  let areExtensionsIsolated = config.isolateExtensions;
 
   // chrome.storage should exist, since the extension has the permission, and
   // the storage api is allowed in content scripts.
   if (!chrome.storage) {
     console.log("Error: chrome.storage doesn't exist; it should");
     success = false;
   }
 
   let checkPrivilegedApi = function(api, name) {
-    if (api && !areExtensionsIsolated) {
-      console.log("Error: " + name +
-                  " exists, but shouldn't without isolated extensions.");
-      return false;
-    }
-    if (!api && areExtensionsIsolated) {
-      console.log("Error: " + name +
-                  " doesn't exist, but should with isolated extensions.");
-      return false;
-    }
-    return true;
+    if (api)
+      return true;
+
+    console.log('Error: ' + name + ' doesn\'t exist, but should.');
+    return false;
   };
 
   // For other permissions, they should only be available if this is a trusted
   // extension process - which is the case only when site isolation is enabled
   // for extensions. The whole of chrome.bookmarks (arbitrary unprivileged) is
   // unavailable without site isolation.
   success = success && checkPrivilegedApi(chrome.bookmarks, 'chrome.bookmarks');
   // We test chrome.tabs as a special case, because it's a dependency of the
   // partially unprivileged chrome.extension.
   success = success && checkPrivilegedApi(chrome.tabs, 'chrome.tabs');
   // And parts of chrome.extension should be unavailable to unprivileged
   // contexts.
   success = success && checkPrivilegedApi(chrome.extension.getViews,
                                           'chrome.extension.getViews');
 
   chrome.extension.sendRequest({success: success});
 });