bluetooth: Add histograms for readValue and writeValue outcomes

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 23a5fdc465cedddf752a08c0dc952a38c72d9a60..9ed9023837bbe568c4e67c35eb82efc626dfc11f 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2752,6 +2752,32 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Bluetooth.Web.Characteristic.ReadValue.Outcome"
+    enum="WebBluetoothGATTOperationOutcome">
+  <owner>jyasskin@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <owner>scheib@chromium.org</owner>
+  <summary>
+    Records the outcome of a call to characteristic.readValue(). Use to know
+    what types of errors users are seeing. The results will be used to determine
+    how common this errors are and if we need to provide better error messages
+    to the users.
+  </summary>
+</histogram>
+
+<histogram name="Bluetooth.Web.Characteristic.WriteValue.Outcome"
+    enum="WebBluetoothGATTOperationOutcome">
+  <owner>jyasskin@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <owner>scheib@chromium.org</owner>
+  <summary>
+    Records the outcome of a call to characteristic.writeValue(). Use to know
+    what types of errors users are seeing. The results will be used to determine
+    how common this errors are and if we need to provide better error messages
+    to the users.
+  </summary>
+</histogram>
+
 <histogram name="Bluetooth.Web.ConnectGATT.Outcome"
     enum="WebBluetoothConnectGATTOutcome">
   <owner>jyasskin@chromium.org</owner>
@@ -71969,6 +71995,22 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="5" label="Characteristic.writeValue()"/>
 </enum>
 
+<enum name="WebBluetoothGATTOperationOutcome" type="int">
+  <int value="0" label="Success"/>
+  <int value="1" label="No Device"/>
+  <int value="2" label="No Service"/>
+  <int value="3" label="No Characteristic"/>
+  <int value="4" label="No Descriptor"/>
+  <int value="5" label="Unknown"/>
+  <int value="6" label="Failed"/>
+  <int value="7" label="In Progress"/>
+  <int value="8" label="Invalid Length"/>
+  <int value="9" label="Not Permitted"/>
+  <int value="10" label="Not Authorized"/>
+  <int value="11" label="Not Paired"/>
+  <int value="12" label="Not Supported"/>
+</enum>
+
 <enum name="WebBluetoothGetCharacteristicOutcome" type="int">
   <int value="0" label="Success"/>
   <int value="1" label="No device"/>