--- a/dom/notification/Notification.cpp
+++ b/dom/notification/Notification.cpp
@@ -651,16 +651,18 @@ nsresult
 NotificationPermissionRequest::ResolvePromise()
 {
   nsresult rv = NS_OK;
   if (mCallback) {
     ErrorResult error;
     mCallback->Call(mPermission, error);
     rv = error.StealNSResult();
   }
+  Telemetry::Accumulate(
+    Telemetry::WEB_NOTIFICATION_REQUEST_PERMISSION_CALLBACK, !!mCallback);
   mPromise->MaybeResolve(mPermission);
   return rv;
 }
 
 NS_IMETHODIMP
 NotificationPermissionRequest::GetTypes(nsIArray** aTypes)
 {
   nsTArray<nsString> emptyOptions;

--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -10052,10 +10052,17 @@
   },
   "PLUGIN_DRAWING_MODEL": {
     "alert_emails": ["danderson@mozilla.com"],
     "expires_in_version": "never",
     "kind": "enumerated",
     "bug_numbers": [1229961],
     "n_values": 12,
     "description": "Plugin drawing model. 0 when windowed, otherwise NPDrawingModel + 1."
+  },
+  "WEB_NOTIFICATION_REQUEST_PERMISSION_CALLBACK": {
+    "alert_emails": ["push@mozilla.com"],
+    "expires_in_version": "55",
+    "bug_numbers": [1241278],
+    "kind": "boolean",
+    "description": "Usage of the deprecated Notification.requestPermission() callback argument"
   }
 }