media: Add UMA to report media pipeline start result

media/base/pipeline_impl.cc

Index: media/base/pipeline_impl.cc
diff --git a/media/base/pipeline_impl.cc b/media/base/pipeline_impl.cc
index 0590d00cc550f21be7bc6842bbac941a4d516cde..d739dce1e7639a8d2b0fb2cb92e228f0ca7ddd1e 100644
--- a/media/base/pipeline_impl.cc
+++ b/media/base/pipeline_impl.cc
@@ -756,6 +756,11 @@ void PipelineImpl::RendererWrapper::CompleteSeek(base::TimeDelta seek_time,
   DCHECK(media_task_runner_->BelongsToCurrentThread());
   DCHECK(state_ == kStarting || state_ == kSeeking || state_ == kResuming);
 
+  if (state_ == kStarting) {
+    UMA_HISTOGRAM_ENUMERATION("Media.PipelineStatus.Start", status,
+                              PIPELINE_STATUS_MAX + 1);
+  }
+
   DCHECK(pending_callbacks_);
   pending_callbacks_.reset();