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

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index d1fb95fa83a5181b9aa6eb1bcde3230152ac6389..d873d9d838a25c1ca42c89901f1b816ba7071cc6 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -777,6 +777,10 @@ other types of suffix sets.
   <summary>The version of glibc used. (Linux only)</summary>
 </histogram>
 
+<histogram name="Media.AudioRendererEvents" enum="AudioRendererEvents">
+  <summary>Captures statistics for various AudioRendererImpl events.</summary>
+</histogram>
+
 <histogram name="Media.DetectedAudioCodec" enum="FFmpegCodecs">
   <summary>Audio codec used in HTML5 media.</summary>
 </histogram>
@@ -4142,6 +4146,11 @@ other types of suffix sets.
   <int value="1" label="Abandoned"/>
 </enum>
 
+<enum name="AudioRendererEvents" type="int">
+  <int value="0" label="Initialized"/>
+  <int value="1" label="Runtime error"/>
+</enum>
+
 <enum name="AutocheckoutBubble" type="int">
   <int value="0" label="Created"/>
   <int value="1" label="Accepted"/>