Add detection for repeated audio in capturing.

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 c7a6b843898f0197b5982f07a03c6fc62acfc264..1e4c135affab4da5e318d7cbafe54d851392dd97 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -17061,6 +17061,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.AudioCapturerRepetition" units="RepetitionPatternId">

[Henrik Grunell, 2015/10/01 16:06:01]

What is RepetitionPatternId? You'll need to specify it as an enum= and define it
below in the enum section. See other histograms.

+  <owner>minyue@chromium.org</owner>
+  <summary>
+    Captures bit-exact audio repetitions of pre-defined patterns. The ID of the
+    repetition pattern is reported on each occurance. Ideally, no reports should
+    be generated.
+  </summary>
+</histogram>
+
 <histogram name="Media.AudioChannelLayout" enum="ChannelLayout">
   <owner>dalecurtis@chromium.org</owner>
   <summary>Audio channel layout in HTML5 media.</summary>