Fix chromium-style warnings in webrtc/sound/.

webrtc/sound/sound.gyp

 # Copyright (c) 2014 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.
 
 {
   'includes': [ '../build/common.gypi', ],
   'targets': [
     {
       'target_name': 'rtc_sound',
       'type': 'static_library',
       'dependencies': [
         '<(webrtc_root)/base/base.gyp:rtc_base',
       ],
       'sources': [
         'automaticallychosensoundsystem.h',
         'nullsoundsystem.cc',
         'nullsoundsystem.h',
         'nullsoundsystemfactory.cc',
         'nullsoundsystemfactory.h',
         'platformsoundsystem.cc',
         'platformsoundsystem.h',
         'platformsoundsystemfactory.cc',
         'platformsoundsystemfactory.h',
         'sounddevicelocator.h',
+        'soundinputstreaminterface.cc',
         'soundinputstreaminterface.h',
+        'soundoutputstreaminterface.cc',
         'soundoutputstreaminterface.h',
         'soundsystemfactory.h',
         'soundsysteminterface.cc',
         'soundsysteminterface.h',
         'soundsystemproxy.cc',
         'soundsystemproxy.h',
       ],
       'conditions': [
         ['OS=="linux"', {
           'sources': [
             'alsasoundsystem.cc',
             'alsasoundsystem.h',
             'alsasymboltable.cc',
             'alsasymboltable.h',
             'linuxsoundsystem.cc',
             'linuxsoundsystem.h',
             'pulseaudiosoundsystem.cc',
             'pulseaudiosoundsystem.h',
             'pulseaudiosymboltable.cc',
             'pulseaudiosymboltable.h',
           ],
         }],
       ],
     },
   ],
 }