Add metric for tracking media playback utilization.

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 86869a435ce1fb5ee9a688b389ca56f5a3779b27..efc195e94dbcc24883314fb2cf2e2273e8963275 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -25832,6 +25832,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.HasEverPlayed" enum="BooleanHasPlayed">
+  <owner>dalecurtis@chromium.org</owner>
+  <summary>
+    Whether a given WebMediaPlayer instance, after preload, started playback;
+    recorded once at time of player destruction.
+  </summary>
+</histogram>
+
 <histogram name="Media.HighLatencyAudioCaptureStartupSuccess"
     enum="AudioCaptureStartupResult">
   <owner>maxmorin@chromium.org</owner>
@@ -80925,6 +80933,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Has path"/>
 </enum>
 
+<enum name="BooleanHasPlayed" type="int">
+  <int value="0" label="Never played"/>
+  <int value="1" label="Played"/>
+</enum>
+
 <enum name="BooleanHasSeekPenalty" type="int">
   <int value="0" label="Has no seek penalty (e.g. is flash memory)"/>
   <int value="1" label="Has seek penalty (e.g. spinning disk)"/>