Update Twemoji to Unicode 9

[pento]

The latest Twemoji images have landed.

To-do:

• Upload assets to s.w.org, in a new directory, due to CDN changes
• Update twemoji.js
• Add a Unicode 9 test to the compatibility shim

[pento]

@ocean90: If you're okay with this squeezing into 4.6, I can get it done on Monday.

[jorbin]

I think this should absolutely be done for 4.6. As a user, I want all emoji that I use on my site to work for all end users.

[ocean90]

@ocean90: If you're okay with this squeezing into 4.6, I can get it done on Monday.

Do it.

Add a Unicode 9 test to the compatibility shim

Is it possible to show Twemoji images only if the current page uses Unicode 9 characters?

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List of the new emoji characters: ​http://www.unicode.org/emoji/charts/emoji-versions.html#v9.0_2016

[pento]

Replying to ocean90:

Is it possible to show Twemoji images only if the current page uses Unicode 9 characters?

Nope.

twemoji.js doesn't support this behaviour, it's all or nothing. Also, only replacing some emoji looks weird, you end up with clashing styles.

I'm not too concerned, I expect the browsers to catch up pretty quickly - they all seem to be on the ball lately.

[superpoincare]

Not sure if I need to add a new bug report or it's okay here.

The s.w.org folder for svgs need cache headers like expiry and/or max-age. Also the files need to be compressed.

See Google pagespeed complaining on this. Wasn't for pngs.

[pento]

Unicode 9 assets are now on the s.w.org CDN.

Due to CDN changes, they're now in a subdirectory of the original emoji directory.

​https://s.w.org/images/core/emoji/2/svg/1f937.svg

[pento]

In 38087:

Emoji: Update to Unicode 9.0 emoji.

This includes a new test in the emoji loader, to see if the browser supports rendering Unicode 9.0 emoji, as well as an update to twemoji.js, to load Unicode 9.0 twemoji images.

The default CDN location for loading Twemoji images has changed, moving to a versioned subdirectory. This allows updates without needing to purge the CDN.

Fixes #37361.