--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -788,16 +788,17 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'DOMTransactionEvent.webidl',
     'DownloadEvent.webidl',
     'ErrorEvent.webidl',
     'FontFaceSetLoadEvent.webidl',
     'HashChangeEvent.webidl',
     'IccChangeEvent.webidl',
     'ImageCaptureErrorEvent.webidl',
     'MediaStreamEvent.webidl',
+    'MediaStreamTrackEvent.webidl',
     'MozCellBroadcastEvent.webidl',
     'MozClirModeEvent.webidl',
     'MozContactChangeEvent.webidl',
     'MozEmergencyCbModeEvent.webidl',
     'MozMessageDeletedEvent.webidl',
     'MozMmsEvent.webidl',
     'MozOtaStatusEvent.webidl',
     'MozSettingsEvent.webidl',
@@ -829,17 +830,16 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'UDPMessageEvent.webidl',
     'UserProximityEvent.webidl',
     'USSDReceivedEvent.webidl',
     'WebGLContextEvent.webidl',
 ]
 
 if CONFIG['MOZ_WEBRTC']:
     GENERATED_EVENTS_WEBIDL_FILES += [
-        'MediaStreamTrackEvent.webidl',
         'RTCDataChannelEvent.webidl',
         'RTCPeerConnectionIceEvent.webidl',
         'RTCTrackEvent.webidl',
     ]
 
 if CONFIG['MOZ_WEBSPEECH']:
     GENERATED_EVENTS_WEBIDL_FILES += [
         'SpeechRecognitionEvent.webidl',