Twenty Fourteen: Add "chat" post format support

[alexvorn2]

Currently we have: 'aside', 'image', 'video', 'audio', 'quote', 'link', 'gallery' but no chat...

This ticket is for adding the chat to the list:

	add_theme_support( 'post-formats', array(
		'aside', 'image', 'video', 'audio', 'quote', 'link', 'gallery',
	) );

[celloexpressions]

Are there any particular reasons you'd like to add support for the chat format? For example, I outlined some use cases when we added support for the audio format in #25807. We don't support every format because there are so many, so I think we should make sure that there are common use cases for this one before adding it.

[SergeyBiryukov]

Replying to celloexpressions:

We don't support every format because there are so many

We already support ​7 out of 9, so I guess the point is just that chat is one of the two missing formats (the other one is status). Would still be good to make sure it's actually needed though.

[DrewAPicture]

Replying to celloexpressions:

Are there any particular reasons you'd like to add support for the chat format? For example, I outlined some use cases when we added support for the audio format in #25807. We don't support every format because there are so many, so I think we should make sure that there are common use cases for this one before adding it.

As this is a "magazine" theme, I'd think that chat transcripts might be a very apt use-case. Think interviews.

[celloexpressions]

If we add chat we might want to add status also, because then that'd be the only one we didn't support, which seems less intentional than leaving two out. I'm curious to know why audio (#25807), chat, and status weren't supported in Further originally (I believe this dates back to then), as that could inform the decision here.

Implementation-wise, this could be as simple as duplicating the handling of other formats, like was done for audio, or we could do something else to distinguish chat.

[lancewillett]

I vote not to add chat post format support to Twenty Fourteen, and in future default themes continue choosing the most common post formats rather than enabling them all.