[ObjC ARC] Converts ios/chrome/test:test_support to ARC.

ios/chrome/test/testing_application_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/test/testing_application_context.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/time/default_clock.h"
 #include "base/time/default_tick_clock.h"
 #include "components/network_time/network_time_tracker.h"
 #import "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #include "net/url_request/url_request_context_getter.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 TestingApplicationContext::TestingApplicationContext()
     : application_locale_("en"),
       local_state_(nullptr),
       chrome_browser_state_manager_(nullptr),
       was_last_shutdown_clean_(false) {
   DCHECK(!GetApplicationContext());
   SetApplicationContext(this);
 }
 
 TestingApplicationContext::~TestingApplicationContext() {
@@ skipping 133 matching lines @@
 CRLSetFetcher* TestingApplicationContext::GetCRLSetFetcher() {
   DCHECK(thread_checker_.CalledOnValidThread());
   return nullptr;
 }
 
 physical_web::PhysicalWebDataSource*
 TestingApplicationContext::GetPhysicalWebDataSource() {
   DCHECK(thread_checker_.CalledOnValidThread());
   return nullptr;
 }