--- a/dom/webidl/MediaKeySystemAccess.webidl
+++ b/dom/webidl/MediaKeySystemAccess.webidl
@@ -17,22 +17,16 @@ dictionary MediaKeySystemMediaCapability
 
 dictionary MediaKeySystemConfiguration {
   DOMString                               label = "";
   sequence<DOMString>                     initDataTypes;
   sequence<MediaKeySystemMediaCapability> audioCapabilities;
   sequence<MediaKeySystemMediaCapability> videoCapabilities;
 
    // TODO: distinctiveIdentifier, persistentState, sessionTypes  
-  
-  // For backwards compatibility with implementations using old
-  // MediaKeySystemOptions paradigm...
-  DOMString            initDataType = "";
-  DOMString            audioType = "";
-  DOMString            videoType = "";
 };
 
 [Pref="media.eme.apiVisible"]
 interface MediaKeySystemAccess {
   readonly    attribute DOMString keySystem;
   [NewObject]
   MediaKeySystemConfiguration getConfiguration();
   [NewObject]