[iOS] Integration of ChromeNetLog and NetExportUI

ios/chrome/test/testing_application_context.cc

 // 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/test/testing_application_context.h"
 
 #include "base/logging.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 
 TestingApplicationContext::TestingApplicationContext()
@@ skipping 51 matching lines @@
 }
 
 policy::BrowserPolicyConnector*
 TestingApplicationContext::GetBrowserPolicyConnector() {
   return nullptr;
 }
 
 rappor::RapporService* TestingApplicationContext::GetRapporService() {
   return nullptr;
 }
+
+net_log::ChromeNetLog* TestingApplicationContext::GetNetLog() {
+  return nullptr;
+}