Remove TreatNullAs=NullString for media interfaces

Source/core/html/HTMLMediaElement.idl

 /*
  * Copyright (C) 2007, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 14 matching lines @@
 
 [
     RuntimeEnabled=Media,
     ActiveDOMObject
 ] interface HTMLMediaElement : HTMLElement {
 
     // error state
     readonly attribute MediaError error;
 
     // network state
-    [Reflect, TreatNullAs=NullString, URL] attribute DOMString src;
+    [Reflect, URL] attribute DOMString src;
     [URL] readonly attribute DOMString currentSrc;
 
     const unsigned short NETWORK_EMPTY = 0;
     const unsigned short NETWORK_IDLE = 1;
     const unsigned short NETWORK_LOADING = 2;
     const unsigned short NETWORK_NO_SOURCE = 3;
     readonly attribute unsigned short networkState;
     attribute DOMString preload;
 
     readonly attribute TimeRanges buffered;
@@ skipping 19 matching lines @@
     attribute double playbackRate;
     readonly attribute TimeRanges played;
     readonly attribute TimeRanges seekable;
     readonly attribute boolean ended;
     [Reflect] attribute boolean autoplay;
     [Reflect] attribute boolean loop;
     void play();
     void pause();
 
     // media controller
-    [Reflect, TreatNullAs=NullString] attribute DOMString mediaGroup;
+    [Reflect] attribute DOMString mediaGroup;
     [CustomSetter] attribute MediaController controller;
 
     // controls
     attribute boolean controls;
     [SetterRaisesException] attribute double volume;
     attribute boolean muted;
     [Reflect=muted] attribute boolean defaultMuted;
 
     // tracks
     [RuntimeEnabled=VideoTrack] readonly attribute TextTrackList textTracks;
@@ skipping 10 matching lines @@
     [RuntimeEnabled=PrefixedEncryptedMedia, RaisesException] void webkitAddKey([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString keySystem, Uint8Array key, optional Uint8Array initData, [Default=NullString] optional DOMString sessionId);
     [RuntimeEnabled=PrefixedEncryptedMedia, RaisesException] void webkitCancelKeyRequest([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString keySystem, [Default=NullString] optional DOMString sessionId);
 
     [RuntimeEnabled=PrefixedEncryptedMedia] attribute EventHandler onwebkitkeyadded;
     [RuntimeEnabled=PrefixedEncryptedMedia] attribute EventHandler onwebkitkeyerror;
     [RuntimeEnabled=PrefixedEncryptedMedia] attribute EventHandler onwebkitkeymessage;
     [RuntimeEnabled=PrefixedEncryptedMedia] attribute EventHandler onwebkitneedkey;
 
     [RuntimeEnabled=EncryptedMedia, Conditional=ENCRYPTED_MEDIA_V2] attribute MediaKeys mediaKeys;
 };