Make canPlayType()'s keySystem argument depend on PrefixedEncryptedMedia

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 28 matching lines @@
 
     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;
     void load();
-    DOMString canPlayType(DOMString type, [Default=Undefined, TreatUndefinedAs=NullString] optional DOMString? keySystem);
+    DOMString canPlayType(DOMString type);

[ddorwin, 2015/01/27 18:40:01]

Does the generated code automatically call HTMLMediaElement::canPlayType(type,
<isNull() string>)?

[philipj_slow, 2015/01/28 06:10:27]

I'm not sure what the <isNull() string> syntax means, but you get a generated
canPlayType1Method and canPlayType2Method. Both use "V8StringResource<> type"
and the latter has "V8StringResource<TreatNullAndUndefinedAsNullString>
keySystem", so nothing has change when it comes to null/undefined.

+    [RuntimeEnabled=PrefixedEncryptedMedia] DOMString canPlayType(DOMString type, [TreatUndefinedAs=NullString] DOMString? keySystem);

[ddorwin, 2015/01/27 18:40:02]

Do we still need the '?'?

[ddorwin, 2015/01/27 18:40:48]

Should we move the DeprecateAs here too for consistency? Maybe in a separate CL.

[philipj_slow, 2015/01/28 06:10:27]

It was never needed AFAICT, but it doesn't seem worth changing the behavior of
canPlayType("", null) and canPlayType("", undefined) when this is going to be
removed soonish anyway.

[philipj_slow, 2015/01/28 06:10:27]

I'll do it here. It's not exactly equivalent, but close enough, and having it in
the IDL wherever possible is nice.

[philipj_slow, 2015/01/28 06:46:26]

Actually the nullability was per the original spec:
https://github.com/w3c/encrypted-media/commit/04bb2c8775b718b56934484e3b76f98...

In any event I'll leave it alone.

 
     // ready state
     const unsigned short HAVE_NOTHING = 0;
     const unsigned short HAVE_METADATA = 1;
     const unsigned short HAVE_CURRENT_DATA = 2;
     const unsigned short HAVE_FUTURE_DATA = 3;
     const unsigned short HAVE_ENOUGH_DATA = 4;
     readonly attribute unsigned short readyState;
     readonly attribute boolean seeking;
 
@@ skipping 28 matching lines @@
     [RaisesException] TextTrack addTextTrack(TextTrackKind kind, optional DOMString label = "", optional DOMString language = "");
 
     // WebKit extensions
 
     // The number of bytes consumed by the media decoder.
     [MeasureAs=PrefixedAudioDecodedByteCount] readonly attribute unsigned long webkitAudioDecodedByteCount;
     [MeasureAs=PrefixedVideoDecodedByteCount] readonly attribute unsigned long webkitVideoDecodedByteCount;
 
     [Reflect, RuntimeEnabled=SubresourceIntegrity] attribute DOMString integrity;
 };