More tracing for audio rendering

content/browser/renderer_host/media/audio_sync_reader.cc

Index: content/browser/renderer_host/media/audio_sync_reader.cc
diff --git a/content/browser/renderer_host/media/audio_sync_reader.cc b/content/browser/renderer_host/media/audio_sync_reader.cc
index 943cedb4d0b6a839e1e1f82a95c77a3f9cce4e58..74cfa13856bfb452756d6243078f06b8ed9341c7 100644
--- a/content/browser/renderer_host/media/audio_sync_reader.cc
+++ b/content/browser/renderer_host/media/audio_sync_reader.cc
@@ -10,6 +10,7 @@
 #include "base/memory/shared_memory.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/stringprintf.h"
+#include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/public/common/content_switches.h"
@@ -164,6 +165,7 @@ bool AudioSyncReader::PrepareForeignSocket(
 }
 
 bool AudioSyncReader::WaitUntilDataIsReady() {
+  TRACE_EVENT0("audio", "AudioSyncReader::WaitUntilDataIsReady");
   base::TimeDelta timeout = maximum_wait_time_;
   const base::TimeTicks start_time = base::TimeTicks::Now();
   const base::TimeTicks finish_time = start_time + timeout;
@@ -201,7 +203,8 @@ bool AudioSyncReader::WaitUntilDataIsReady() {
   // Receive timed out or another error occurred.  Receive can timeout if the
   // renderer is unable to deliver audio data within the allotted time.
   if (!bytes_received || renderer_buffer_index != buffer_index_) {
-    DVLOG(2) << "AudioSyncReader::WaitUntilDataIsReady() timed out.";
+    TRACE_EVENT_INSTANT0("audio", "AudioSyncReader::Read timed out",

[DaleCurtis, 2016/08/19 16:49:00]

Be neat if we could make this show up in a red color or something :)

[o1ka, 2016/08/23 07:16:00]

Would be really cool, but looks like they don't have that.

+                         TRACE_EVENT_SCOPE_THREAD);
 
     base::TimeDelta time_since_start = base::TimeTicks::Now() - start_time;
     UMA_HISTOGRAM_CUSTOM_TIMES("Media.AudioOutputControllerDataNotReady",