WebAudio: record whether user gesture was available and provided.

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 d02f2bee6c44aa65f3acdad464229c26c46b5b53..0f4057ef5c6b22ef39b12d40007cf83844bcfd4f 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -60309,6 +60309,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="WebAudio.UserGesture" enum="UserGestureRequirement">
+  <owner>mlamouri@chromium.org</owner>
+  <summary>
+    Records whether WebAudio had a user gesture requirement and whether it was
+    fulfilled.
+  </summary>
+</histogram>
+
 <histogram name="WebController.CertVerificationErrorsCacheHit"
     enum="BooleanCacheHit">
   <owner>eugenebut@chromium.org</owner>
@@ -90243,6 +90251,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="3" label="Stable"/>
 </enum>
 
+<enum name="UserGestureRequirement" type="int">
+  <int value="0" label="Required and available"/>
+  <int value="1" label="Required and not available"/>
+  <int value="2" label="Not required and available"/>
+  <int value="3" label="Not required and not available"/>
+</enum>
+
 <enum name="UserInitiatedEvent" type="int">
   <int value="0" label="WiFi Scan"/>
 </enum>