bluetooth: Add histogram for WebBluetooth actions

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 e16727c2aa6bed7f73d2ba3fc283b9ad22979c3b..5f82b41614db9f94822e61d9855a2f541c737d60 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2724,6 +2724,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Bluetooth.Web.FunctionCall.Count" enum="WebBluetoothFunction">
+  <owner>jyasskin@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <owner>scheib@chromium.org</owner>
+  <summary>
+    Counts the number of times each call to a WebBluetooth function is done.
+  </summary>
+</histogram>
+
 <histogram name="Bookmarks.LaunchDepth">
   <owner>yfriedman@chromium.org</owner>
   <summary>
@@ -71018,6 +71027,15 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="5" label="Policy"/>
 </enum>
 
+<enum name="WebBluetoothFunction" type="int">
+  <int value="0" label="requestDevice()"/>
+  <int value="1" label="connectGATT()"/>
+  <int value="2" label="getPrimaryService()"/>
+  <int value="3" label="getCharacteristic()"/>
+  <int value="4" label="Characteristic.readValue()"/>
+  <int value="5" label="Characteristic.writeValue()"/>
+</enum>
+
 <enum name="WebFontCacheHit" type="int">
   <int value="0" label="Miss"/>
   <int value="1" label="Hit"/>