Add UMA for droppedframes count

media/base/pipeline.cc

 // Copyright (c) 2012 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 "media/base/pipeline.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 606 matching lines @@
 
     return;
   }
 
   stop_cb_ = stop_cb;
 
   // We may already be stopping due to a runtime error.
   if (state_ == kStopping)
     return;
 
+  PipelineStatistics stats = GetStatistics();
+  UMA_HISTOGRAM_COUNTS("Media.DroppedFrameCount", stats.video_frames_dropped);

[scherkus (not reviewing), 2014/08/26 21:41:04]

here's where things get subtle/tricky ... do we want to record this stat even
for Pipelines that don't contain video? (e.g., mp3s)

do we want to record this stat for Pipelines that never even successfully start
playing?

+
   SetState(kStopping);
   pending_callbacks_.reset();
   DoStop(base::Bind(&Pipeline::OnStopCompleted, weak_factory_.GetWeakPtr()));
 }
 
 void Pipeline::ErrorChangedTask(PipelineStatus error) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK_NE(PIPELINE_OK, error) << "PIPELINE_OK isn't an error!";
 
   media_log_->AddEvent(media_log_->CreatePipelineErrorEvent(error));
@@ skipping 286 matching lines @@
 void Pipeline::StartClockIfWaitingForTimeUpdate_Locked() {
   lock_.AssertAcquired();
   if (interpolation_state_ != INTERPOLATION_WAITING_FOR_AUDIO_TIME_UPDATE)
     return;
 
   interpolation_state_ = INTERPOLATION_STARTED;
   interpolator_->StartInterpolating();
 }
 
 }  // namespace media