Remove non-ARC code from the codebase.

webrtc/test/testsupport/iosfileutils.mm

 /*
  *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #if defined(WEBRTC_IOS)
 
-#if !defined(__has_feature) || !__has_feature(objc_arc)
-#error "This file requires ARC support."
-#endif
-
 #import <Foundation/Foundation.h>
 #include <string.h>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/typedefs.h"
 #include "webrtc/sdk/objc/Framework/Classes/helpers.h"
 
 namespace webrtc {
 namespace test {
 
@@ skipping 31 matching lines @@
     if (tempDir == nil)
         tempDir = @"/tmp";
     return StdStringFromNSString(tempDir);
   }
 }
 
 }  // namespace test
 }  // namespace webrtc
 
 #endif  // defined(WEBRTC_IOS)