Use TextTrackKind enum in HTMLMediaElement.addTextTrack IDL signature

Use TextTrackKind enum in HTMLMediaElement.addTextTrack IDL signature

With https://codereview.chromium.org/831483004 is becomes possible to use
the TextTrackKind enum defined in TextTrack.idl without redefining it.
Do that, and also update the spec. steps in HTMLMediaElement::addTextTrack
to match a later version. Move the call to setReadinessState() since it
does not cause any side-effects, but add a comment about a potential issue
with the current order of setup.
Also add default values to the optional arguments and drop the unneeded
forwarders. This also means that undefined will now be properly handled
for these arguments.
Update tests to reflect the new exception thrown as well as the behavior
with undefined.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188644

[fs, 2015-01-16 15:18:24]

fs@opera.com changed reviewers:
+ philipj@opera.com

[philipj_slow, 2015-01-19 14:26:29]

lgtm with enthusiasm and nits \o/ <- title of my next album

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
File Source/core/html/HTMLMediaElement.cpp (right):

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:2751: // 4.8.14.12.5 Text track API
Given the direct link this isn't very useful, and is guaranteed to be stale
soon.

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:2775: // same task source as the
'addtrack' event (see above), meaning the order
s/meaning//

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:2776: // is wrong. (If the 'change' event
should be fired at all in this case...)
The spec says "Whenever a text track that is in a media element's list of text
tracks has its text track mode change value" so the change event should not be
fired. I think I filed or commented on a spec bug about this once. Perhaps
fixing the order in this function to match the spec would fix the problem, but
no reason to do it in this CL unless you think it fits.

[fs, 2015-01-19 14:55:06]

On 2015/01/19 14:26:29, philipj wrote:
> lgtm with enthusiasm and nits \o/ <- title of my next album

/me pre-orders

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
File Source/core/html/HTMLMediaElement.cpp (right):

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:2751: // 4.8.14.12.5 Text track API
On 2015/01/19 14:26:29, philipj wrote:
> Given the direct link this isn't very useful, and is guaranteed to be stale
> soon.

Dropped.

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:2775: // same task source as the
'addtrack' event (see above), meaning the order
On 2015/01/19 14:26:29, philipj wrote:
> s/meaning//

Done.

https://codereview.chromium.org/790633003/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:2776: // is wrong. (If the 'change' event
should be fired at all in this case...)
On 2015/01/19 14:26:29, philipj wrote:
> The spec says "Whenever a text track that is in a media element's list of text
> tracks has its text track mode change value" so the change event should not be
> fired. I think I filed or commented on a spec bug about this once. Perhaps
> fixing the order in this function to match the spec would fix the problem, but
> no reason to do it in this CL unless you think it fits.

Yes, my interpretation was that 'change' should not be fired here. The code-flow
is a bit elaborate here though, so I opted to leave the issue alone for now.

I updated the comment (final parenthesis) to state that 'change' should not be
fired at all.

[fs, 2015-01-19 15:10:04]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2015-01-19 15:10:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/790633003/20001

[commit-bot: I haz the power, 2015-01-19 17:48:58]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=188644