Add FID deprecation when FID metric measured

Author: ankur22

internal/js/modules/k6/browser/common/frame_session.go

@@ -326,6 +326,9 @@ func (fs *FrameSession) onEventBindingCalled(event *cdpruntime.EventBindingCalle
 	}
 }
 
+//nolint:gochecknoglobals
+var fidDeprecationWarningOnce sync.Once
+
 func (fs *FrameSession) parseAndEmitWebVitalMetric(object string) error {
 	fs.logger.Debugf("FrameSession:parseAndEmitWebVitalMetric", "object:%s", object)
 
@@ -345,6 +348,12 @@ func (fs *FrameSession) parseAndEmitWebVitalMetric(object string) error {
 		return fmt.Errorf("json couldn't be parsed: %w", err)
 	}
 
+	if wv.Name == "FID" {
+		fidDeprecationWarningOnce.Do(func() {
+			fs.logger.Warnf("MetricDeprecation", "browser_web_vital_fid has been deprecated and superseded by browser_web_vital_inp")
+		})
+	}
+
 	metric, ok := fs.k6Metrics.WebVitals[wv.Name]
 	if !ok {
 		return fmt.Errorf("metric not registered %q", wv.Name)