Added UMA metrics for MediaSourcePlayer and MediaCodecPlayer

media/base/android/audio_decoder_job.cc

Index: media/base/android/audio_decoder_job.cc
diff --git a/media/base/android/audio_decoder_job.cc b/media/base/android/audio_decoder_job.cc
index 07b828882a29e5d32137c2db08ad08a509308950..0fa322cca9249b0342198b3b502c41bf617e6198 100644
--- a/media/base/android/audio_decoder_job.cc
+++ b/media/base/android/audio_decoder_job.cc
@@ -8,6 +8,7 @@
 #include "base/lazy_instance.h"
 #include "base/threading/thread.h"
 #include "media/base/android/media_codec_bridge.h"
+#include "media/base/android/media_statistics.h"
 #include "media/base/audio_timestamp_helper.h"
 #include "media/base/timestamp_constants.h"
 
@@ -35,10 +36,12 @@ base::LazyInstance<AudioDecoderThread>::Leaky
 
 AudioDecoderJob::AudioDecoderJob(
     const base::Closure& request_data_cb,
-    const base::Closure& on_demuxer_config_changed_cb)
+    const base::Closure& on_demuxer_config_changed_cb,
+    FrameStatistics* frame_statistics)
     : MediaDecoderJob(g_audio_decoder_thread.Pointer()->task_runner(),
                       request_data_cb,
-                      on_demuxer_config_changed_cb),
+                      on_demuxer_config_changed_cb,
+                      frame_statistics),
       audio_codec_(kUnknownAudioCodec),
       num_channels_(0),
       config_sampling_rate_(0),
@@ -106,14 +109,28 @@ void AudioDecoderJob::ReleaseOutputBuffer(
     int64 head_position = (static_cast<AudioCodecBridge*>(
         media_codec_bridge_.get()))->PlayOutputBuffer(
             output_buffer_index, size, offset);
+
+    base::TimeTicks current_time = base::TimeTicks::Now();
+
     size_t new_frames_count = size / bytes_per_frame_;
     frame_count_ += new_frames_count;
     audio_timestamp_helper_->AddFrames(new_frames_count);
     int64 frames_to_play = frame_count_ - head_position;
     DCHECK_GE(frames_to_play, 0);
+
+    const base::TimeDelta last_buffered =
+        audio_timestamp_helper_->GetTimestamp();
+
     current_presentation_timestamp =
-        audio_timestamp_helper_->GetTimestamp() -
+        last_buffered -
         audio_timestamp_helper_->GetFrameDuration(frames_to_play);
+
+    if (frame_statistics_ && !next_frame_time_limit_.is_null() &&

[qinmin, 2015/09/29 23:47:44]

I think we can just check the head_position variable to determine if audio
underruns, no?

[Tima Vaisburd, 2015/09/30 18:50:09]

Having the delay makes it possible to track it down if we want to do it later,
e.g. make a histogram of delay. It also make it similar to video frame
statistics so we can pass a smaller frame statistics object into decoders. What
do you think?

+        next_frame_time_limit_ < current_time)
+      frame_statistics_->AddLateFrame(current_time - next_frame_time_limit_);

[qinmin, 2015/09/29 23:47:44]

{} needed

[Tima Vaisburd, 2015/09/30 18:50:09]

Done.

+
+    next_frame_time_limit_ =
+        current_time + (last_buffered - current_presentation_timestamp);
   } else {
     current_presentation_timestamp = kNoTimestamp();
   }