Optionally disable APM limiter in AudioMixer.

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("../../webrtc.gni")
 
 group("audio_mixer") {
   public_deps = [
     ":audio_frame_manipulator",
     ":audio_mixer_impl",
   ]
 }
 
 rtc_static_library("audio_mixer_impl") {
   sources = [
     "audio_mixer_impl.cc",
     "audio_mixer_impl.h",
     "default_output_rate_calculator.cc",
     "default_output_rate_calculator.h",
+    "frame_combiner.cc",
+    "frame_combiner.h",
     "output_rate_calculator.h",
   ]
 
   public = [
     "audio_mixer_impl.h",
+    "default_output_rate_calculator.h",  # For creating a mixer with limiter disabled.
   ]
 
   public_deps = [
     "../../api:audio_mixer_api",
   ]
 
   deps = [
     ":audio_frame_manipulator",
     "../..:webrtc_common",
     "../../audio/utility:audio_frame_operations",
@@ skipping 42 matching lines @@
     ]
 
     # TODO(jschuh): bugs.webrtc.org/1348: fix this warning.
     configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }