Added code for MediaStreamAudioTrackProcessing Finch Experiment enabling

content/renderer/media/media_stream_audio_processor.cc

Index: content/renderer/media/media_stream_audio_processor.cc
diff --git a/content/renderer/media/media_stream_audio_processor.cc b/content/renderer/media/media_stream_audio_processor.cc
index ef693b241cee6b352a6c28efe5ba97d58cacd7a6..640ab05dd87655c2f00029eecd439a38263f5802 100644
--- a/content/renderer/media/media_stream_audio_processor.cc
+++ b/content/renderer/media/media_stream_audio_processor.cc
@@ -6,6 +6,7 @@
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
+#include "base/metrics/field_trial.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"
@@ -264,8 +265,11 @@ void MediaStreamAudioProcessor::InitializeAudioProcessingModule(
     const blink::WebMediaConstraints& constraints, int effects,
     MediaStreamType type) {
   DCHECK(!audio_processing_);
+  const std::string group_name =
+      base::FieldTrialList::FindFullName("MediaStreamAudioTrackProcessing");
   if (!CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableAudioTrackProcessing)) {
+          switches::kEnableAudioTrackProcessing) &&
+      group_name != "Enabled") {
     return;
   }