Add Media.AudioRendererEvents histogram to measure how often OnRenderError() is called.

media/filters/audio_renderer_impl.cc

Index: media/filters/audio_renderer_impl.cc
diff --git a/media/filters/audio_renderer_impl.cc b/media/filters/audio_renderer_impl.cc
index 64ec80e27d2818e739f5a8a6c3188722d1fc0e6b..fb5585fb47522625a0aa2103e7488978daf70266 100644
--- a/media/filters/audio_renderer_impl.cc
+++ b/media/filters/audio_renderer_impl.cc
@@ -14,6 +14,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop_proxy.h"
+#include "base/metrics/histogram.h"
 #include "media/audio/audio_util.h"
 #include "media/base/audio_splicer.h"
 #include "media/base/bind_to_loop.h"
@@ -25,6 +26,20 @@
 
 namespace media {
 
+namespace {
+
+enum AudioRendererEvent {
+  INITIALIZED,
+  RENDER_ERROR,
+  MAX_EVENTS
+};
+
+void HistogramRendererEvent(AudioRendererEvent event) {
+  UMA_HISTOGRAM_ENUMERATION("Media.AudioRendererEvents", event, MAX_EVENTS);
+}
+
+}  // namespace
+
 AudioRendererImpl::AudioRendererImpl(
     const scoped_refptr<base::MessageLoopProxy>& message_loop,
     media::AudioRendererSink* sink,
@@ -284,6 +299,8 @@ void AudioRendererImpl::OnDecoderSelected(
 
   state_ = kPaused;
 
+  HistogramRendererEvent(INITIALIZED);
+
   sink_->Initialize(audio_parameters_, weak_this_);
   sink_->Start();
 
@@ -629,6 +646,7 @@ void AudioRendererImpl::UpdateEarliestEndTime_Locked(
 }
 
 void AudioRendererImpl::OnRenderError() {
+  HistogramRendererEvent(RENDER_ERROR);
   disabled_cb_.Run();
 }