Add new traces in Web Audio, MediaStream, and intermediate layers

This is for the detailed audio stack tracing. There have been several
audio performance issues reported from the applications that use
Web Audio and MediaSteam together. We need more information on why
the audio rendering thread or AudioWorkletThread is blocked.

Bug: 1072727
Change-Id: I56d33d6bf471938815c7aba3f8b94ad461f9c3b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145557
Commit-Queue: Hongchan Choi <hongchan@chromium.org>
Reviewed-by: Stephen Nusko <nuskos@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762023}

base/trace_event/builtin_categories.h

@@ -163,6 +163,7 @@
   X("webrtc")                                                            \
   X("xr")                                                                \
   X(TRACE_DISABLED_BY_DEFAULT("animation-worklet"))                      \
+  X(TRACE_DISABLED_BY_DEFAULT("audio"))                                  \
   X(TRACE_DISABLED_BY_DEFAULT("audio-worklet"))                          \
   X(TRACE_DISABLED_BY_DEFAULT("blink.debug"))                            \
   X(TRACE_DISABLED_BY_DEFAULT("blink.debug.display_lock"))               \
@@ -203,6 +204,7 @@
   X(TRACE_DISABLED_BY_DEFAULT("layout_shift.debug"))                     \
   X(TRACE_DISABLED_BY_DEFAULT("lifecycles"))                             \
   X(TRACE_DISABLED_BY_DEFAULT("loading"))                                \
+  X(TRACE_DISABLED_BY_DEFAULT("mediastream"))                            \
   X(TRACE_DISABLED_BY_DEFAULT("memory-infra"))                           \
   X(TRACE_DISABLED_BY_DEFAULT("memory-infra.v8.code_stats"))             \
   X(TRACE_DISABLED_BY_DEFAULT("net"))                                    \

media/base/audio_push_fifo.cc

@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include "base/logging.h"
+#include "base/trace_event/trace_event.h"
 
 namespace media {
 
@@ -27,6 +28,8 @@ void AudioPushFifo::Reset(int frames_per_buffer) {
 }
 
 void AudioPushFifo::Push(const AudioBus& input_bus) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("audio"), "AudioPushFifo::Push");
+
   DCHECK_GT(frames_per_buffer_, 0);
 
   // Fast path: No buffering required.

third_party/blink/renderer/platform/exported/web_media_stream_source.cc

@@ -177,6 +177,9 @@ void ConsumerWrapper::SetFormat(size_t number_of_channels, float sample_rate) {
 }
 
 void ConsumerWrapper::ConsumeAudio(AudioBus* bus, size_t number_of_frames) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("mediastream"),
+               "ConsumerWrapper::ConsumeAudio");
+
   if (!bus)
     return;
 

third_party/blink/renderer/platform/mediastream/media_stream_audio_track.cc

@@ -137,6 +137,9 @@ void MediaStreamAudioTrack::OnSetFormat(const media::AudioParameters& params) {
 
 void MediaStreamAudioTrack::OnData(const media::AudioBus& audio_bus,
                                    base::TimeTicks reference_time) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("mediastream"),
+               "MediaStreamAudioTrack::OnData");
+
   if (!received_audio_callback_) {
     // Add log message with unique this pointer id to mark the audio track as
     // alive at the first data callback.

third_party/blink/renderer/platform/mediastream/media_stream_source.cc

@@ -217,6 +217,9 @@ void MediaStreamSource::GetSettings(WebMediaStreamTrack::Settings& settings) {
 
 void MediaStreamSource::SetAudioFormat(size_t number_of_channels,
                                        float sample_rate) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("mediastream"),
+               "MediaStreamSource::SetAudioFormat");
+
   SendLogMessage(
       String::Format(
           "SetAudioFormat({id=%s}, {number_of_channels=%d}, {sample_rate=%f})",
@@ -230,6 +233,9 @@ void MediaStreamSource::SetAudioFormat(size_t number_of_channels,
 }
 
 void MediaStreamSource::ConsumeAudio(AudioBus* bus, size_t number_of_frames) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("mediastream"),
+               "MediaStreamSource::ConsumeAudio");
+
   DCHECK(requires_consumer_);
   MutexLocker locker(audio_consumers_lock_);
   for (AudioDestinationConsumer* consumer : audio_consumers_)

third_party/blink/renderer/platform/mediastream/webaudio_media_stream_source.cc

@@ -86,6 +86,9 @@ void WebAudioMediaStreamSource::EnsureSourceIsStopped() {
 void WebAudioMediaStreamSource::ConsumeAudio(
     const Vector<const float*>& audio_data,
     size_t number_of_frames) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("mediastream"),
+               "WebAudioMediaStreamSource::ConsumeAudio");
+
   // TODO(miu): Plumbing is needed to determine the actual capture timestamp
   // of the audio, instead of just snapshotting base::TimeTicks::Now(), for
   // proper audio/video sync.  https://crbug.com/335335
@@ -104,6 +107,8 @@ void WebAudioMediaStreamSource::ConsumeAudio(
 void WebAudioMediaStreamSource::DeliverRebufferedAudio(
     const media::AudioBus& audio_bus,
     int frame_delay) {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("mediastream"),
+               "WebAudioMediaStreamSource::DeliverRebufferedAudio");
   const base::TimeTicks reference_time =
       current_reference_time_ +
       base::TimeDelta::FromMicroseconds(