diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index ccb3d59..54c9ec5 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -4532,6 +4532,12 @@
     // OS: O MR
     AUTOFILL_SERVICE_DISABLED_SELF = 1135;
 
+    // Counter showing how long it took (in ms) to show the autofill UI after a field was focused
+    // Tag FIELD_AUTOFILL_SERVICE: Package of service that processed the request
+    // Package: Package of the autofill service
+    // OS: O MR
+    AUTOFILL_UI_LATENCY = 1136;
+
     // ---- End O-MR1 Constants, all O-MR1 constants go above this line ----
 
     // Add new aosp constants above this line.