Make dart:dom implementation types private so they don't muddle the docs.

client/dom/generated/src/frog/MediaController.dart

 
-class MediaControllerJs extends DOMTypeJs implements MediaController native "*MediaController" {
+class _MediaControllerJs extends _DOMTypeJs implements MediaController native "*MediaController" {
 
-  TimeRangesJs get buffered() native "return this.buffered;";
+  _TimeRangesJs get buffered() native "return this.buffered;";
 
   num get currentTime() native "return this.currentTime;";
 
   void set currentTime(num value) native "this.currentTime = value;";
 
   num get defaultPlaybackRate() native "return this.defaultPlaybackRate;";
 
   void set defaultPlaybackRate(num value) native "this.defaultPlaybackRate = value;";
 
   num get duration() native "return this.duration;";
 
   bool get muted() native "return this.muted;";
 
   void set muted(bool value) native "this.muted = value;";
 
   bool get paused() native "return this.paused;";
 
   num get playbackRate() native "return this.playbackRate;";
 
   void set playbackRate(num value) native "this.playbackRate = value;";
 
-  TimeRangesJs get played() native "return this.played;";
+  _TimeRangesJs get played() native "return this.played;";
 
-  TimeRangesJs get seekable() native "return this.seekable;";
+  _TimeRangesJs get seekable() native "return this.seekable;";
 
   num get volume() native "return this.volume;";
 
   void set volume(num value) native "this.volume = value;";
 
   void addEventListener(String type, EventListener listener, [bool useCapture = null]) native;
 
-  bool dispatchEvent(EventJs evt) native;
+  bool dispatchEvent(_EventJs evt) native;
 
   void pause() native;
 
   void play() native;
 
   void removeEventListener(String type, EventListener listener, [bool useCapture = null]) native;
 }