diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index f6de94fab8bb0..b7677c65451dc 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -2200,6 +2200,9 @@ message MetricsEvent {
     // Settings -> Dev options -> Running services
     RUNNING_SERVICES = 404;
 
+    // The dialog shown by 3P intent to change current webview implementation.
+    WEBVIEW_IMPLEMENTATION = 405;
+
     // Add new aosp constants above this line.
     // END OF AOSP CONSTANTS
   }