add srcLang DOM attribute

[revolunet]

Added missing srclang attribute, useful when rendering video elements.

Thanks !

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[revolunet]

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[zpao]

Are there any other <video> related markup DOM properties/attributes that can also be added? #2094 attempted to add some (and some non-markup related ones which is why it didn't get off the ground).

[revolunet]

yes, if you're okay i can add volume, kind, default, playbackRate

(default indicates if its the default subtitle)

[syranide]

http://www.w3.org/TR/html-markup/video.html#video-attributes
http://www.w3.org/TR/html-markup/track.html#track-attributes

I'm pretty sure all of these have to be MUST_USE_ATTRIBUTE too.

[revolunet]

@syranide : thanks, can you please explain the implication of MUST_USE_ATTRIBUTE ? cant find any comment on this in the code

[zpao]

By default React does node.property = newValue. However that doesn't work for everything and for some you must actually do node.setAttribute('name', newValue). MUST_USE_ATTRIBUTE tells React to do the latter here. The inverse is also true where some must be set with the property and will never work with the attribute so we specify MUST_USE_PROPERTY. https://github.com/facebook/react/blob/master/src/renderers/dom/shared/DOMProperty.js#L22-L61 has some comments about this.