Split audio mixer into interface and implementation.

webrtc/modules/audio_mixer/BUILD.gn

 # 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.
 
 import("../../build/webrtc.gni")
 
-config("audio_conference_mixer_config") {
-  include_dirs = [ "../../modules/include" ]
-}
-
-rtc_static_library("audio_mixer") {
+rtc_static_library("audio_mixer_impl") {
+  visibility = [

[kjellander_webrtc, 2016/10/13 00:57:46]

Nice to see this being used. It's probably something we should put more widely
into use along the Slim and modular effort (and put into the design doc).

+    "../../modules/*",
+    "../../audio:audio",

[kjellander_webrtc, 2016/10/13 00:57:47]

sort

[aleloi, 2016/10/13 09:25:22]

Done.

+  ]
   sources = [
     "audio_frame_manipulator.cc",
     "audio_frame_manipulator.h",
-    "audio_mixer.h",
     "audio_mixer_impl.cc",
     "audio_mixer_impl.h",
     "audio_source_with_mix_status.cc",
     "audio_source_with_mix_status.h",
   ]
 
   public = [
-    "audio_mixer.h",
+    "audio_mixer_impl.h",
   ]
 
-  public_configs = [ ":audio_conference_mixer_config" ]
-
   deps = [
     "../..:webrtc_common",
+    "../../api:audio_mixer_api",
     "../../base:rtc_base_approved",
     "../../modules/audio_processing",
     "../../modules/utility",
     "../../system_wrappers",
-    "../../voice_engine:level_indicator",
   ]
 }