Change kEnableAudioTrackProcessing to a disable flag and remove finch code

content/renderer/media/media_stream_audio_processor.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/media_stream_audio_processor.h"
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
-#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "content/public/common/content_switches.h"
 #include "content/renderer/media/media_stream_audio_processor_options.h"
 #include "content/renderer/media/rtc_media_constraints.h"
 #include "content/renderer/media/webrtc_audio_device_impl.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/audio_converter.h"
 #include "media/base/audio_fifo.h"
 #include "media/base/channel_layout.h"
 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
@@ skipping 130 matching lines @@
   const media::AudioParameters sink_params_;
 
   // TODO(xians): consider using SincResampler to save some memcpy.
   // Handles mixing and resampling between input and output parameters.
   media::AudioConverter audio_converter_;
   scoped_ptr<media::AudioBus> audio_wrapper_;
   scoped_ptr<media::AudioFifo> fifo_;
 };
 
 bool MediaStreamAudioProcessor::IsAudioTrackProcessingEnabled() {
-  const std::string group_name =
-      base::FieldTrialList::FindFullName("MediaStreamAudioTrackProcessing");
-  return group_name == "Enabled" || CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableAudioTrackProcessing);
+  return !CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kDisableAudioTrackProcessing);
 }
 
 MediaStreamAudioProcessor::MediaStreamAudioProcessor(
     const blink::WebMediaConstraints& constraints,
     int effects,
     WebRtcPlayoutDataSource* playout_data_source)
     : render_delay_ms_(0),
       playout_data_source_(playout_data_source),
       audio_mirroring_(false),
       typing_detected_(false) {
@@ skipping 320 matching lines @@
 
   StopAecDump();
 
   if (playout_data_source_)
     playout_data_source_->RemovePlayoutSink(this);
 
   audio_processing_.reset();
 }
 
 }  // namespace content