Cleanup of iOS AudioDevice implementation

webrtc/modules/utility/utility.gypi

 # Copyright (c) 2011 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.
 
 {
   'targets': [
     {
       'target_name': 'webrtc_utility',
       'type': 'static_library',
       'dependencies': [
         'audio_coding_module',
         'media_file',
         '<(webrtc_root)/common_audio/common_audio.gyp:common_audio',
         '<(webrtc_root)/system_wrappers/system_wrappers.gyp:system_wrappers',
       ],
       'sources': [
         'interface/audio_frame_operations.h',
         'interface/file_player.h',
         'interface/file_recorder.h',
         'interface/helpers_android.h',
+        'interface/helpers_ios.h',
         'interface/jvm_android.h',
         'interface/process_thread.h',
         'source/audio_frame_operations.cc',
         'source/coder.cc',
         'source/coder.h',
         'source/file_player_impl.cc',
         'source/file_player_impl.h',
         'source/file_recorder_impl.cc',
         'source/file_recorder_impl.h',
         'source/helpers_android.cc',
+        'source/helpers_ios.mm',
         'source/jvm_android.cc',
         'source/process_thread_impl.cc',
         'source/process_thread_impl.h',
       ],
     },
   ], # targets
 }