Move webrtc/audio_*.h to webrtc/api/call

webrtc/common.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': 'webrtc_common',
       'type': 'static_library',
       'sources': [
-        'audio_sink.h',

[the sun, 2016/06/15 09:09:52]

So this bothers me a *little* bit.

The reason audio_sink.h was added here was so that those depending on it would
pull in as little as possible (adding it in webrtc.gyp:webrtc would have
otherwise been the natural place for it). Now, everyone using AudioSinkInterface
implicitly knows about the whole Call API.

Since we're not adding a dependency in those places on the webrtc.gyp:webrtc
target (and everything it pulls in), but only on the call_api target, I think
I'm fine with it though.

[kjellander_webrtc, 2016/06/15 12:32:16]

Yeah, a header should definitely not be present in multiple targets IMO.

         'common_types.cc',
         'common_types.h',
         'config.h',
         'config.cc',
         'engine_configurations.h',
         'typedefs.h',
       ],
     },
   ],
 }