Remove isolated app code from iOS's chrome_browser_state_io_data.

ios/chrome/browser/browser_state/test_chrome_browser_state_isolated_context.mm

 // 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.
 
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state_isolated_context.h"
 
 #include "base/logging.h"
 #include "components/syncable_prefs/pref_service_syncable.h"
 #include "ios/web/public/web_thread.h"
 #include "net/url_request/url_request_test_util.h"
 
 TestChromeBrowserStateWithIsolatedContext::
     TestChromeBrowserStateWithIsolatedContext()
     : TestChromeBrowserState(base::FilePath(),
                              scoped_ptr<syncable_prefs::PrefServiceSyncable>(),
                              TestingFactories(),
                              RefcountedTestingFactories()),
-      main_context_called_(false),
-      request_context_(new net::TestURLRequestContextGetter(
-          web::WebThread::GetTaskRunnerForThread(web::WebThread::IO))) {}
+      main_context_called_(false) {}
 
 TestChromeBrowserStateWithIsolatedContext::
     ~TestChromeBrowserStateWithIsolatedContext() {}
 
 bool TestChromeBrowserStateWithIsolatedContext::MainContextCalled() const {
   return main_context_called_;
 }
 
 IOSWebViewFactoryExternalService
 TestChromeBrowserStateWithIsolatedContext::SharingService() {
   return SSO_AUTHENTICATION;
 }
 
 net::URLRequestContextGetter*
 TestChromeBrowserStateWithIsolatedContext::GetRequestContext() {
   main_context_called_ = true;
   return TestChromeBrowserState::GetRequestContext();
 }
-
-net::URLRequestContextGetter*
-TestChromeBrowserStateWithIsolatedContext::CreateIsolatedRequestContext(
-    const base::FilePath& partition_path) {
-  return request_context_.get();
-}