Record user interactions with MediaSession by action type

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 1383139888c2b53bb63b7437a3000aa1e4c782a3..fab6c5eaf1c3affd5310084a615a845a761aba0f 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -27741,6 +27741,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.Session.UserAction" enum="MediaSessionUserAction">
+  <owner>media-dev@chromium.org</owner>
+  <owner>zqzhang@chromium.org</owner>
+  <summary>
+    The number of times user interacts with MediaSession sorted by action type.
+  </summary>
+</histogram>
+
 <histogram base="true" name="Media.Timeline.DragGestureDuration" units="ms">
 <!-- Name completed by histogram_suffixes name="MediaTimelineWidths" -->
 
@@ -103181,6 +103189,18 @@ from previous Chrome versions.
   <int value="4" label="System Transient Duck"/>
 </enum>
 
+<enum name="MediaSessionUserAction" type="int">
+  <int value="0" label="Play"/>
+  <int value="1" label="Play (default handler)"/>
+  <int value="2" label="Pause"/>
+  <int value="3" label="Pause (default handler)"/>
+  <int value="4" label="Stop (default handler)"/>
+  <int value="5" label="Previous track"/>
+  <int value="6" label="Next track"/>
+  <int value="7" label="Seek backward"/>
+  <int value="8" label="Seek forward"/>
+</enum>
+
 <enum name="MediaStreamRequestResult" type="int">
   <int value="0" label="Ok"/>
   <int value="1" label="Permission Denied"/>