Add expression in.

[Chaoba]

This pr add the interface for expression in. Not include the corresponding pr in core sdk now.
@mapbox/maps-android any suggestion on how to test it?

[tobrun]

You can test your changes by updating the vendor/mapbox-gl-native submodule pin to your PR in mapbox-gl-native. Once that is merged we can set the submodule pin to master.

[Chaoba]

You can test your changes by updating the vendor/mapbox-gl-native submodule pin to your PR in mapbox-gl-native. Once that is merged we can set the submodule pin to master.

That's right. We'd better add an option in RuntimeStyleActivity to test express in, but I am not sure how it should be used in app. Can you give an example about it?

[tobrun]

 ["in", needle: (boolean, string or number), haystack: (array or string)]: boolean

The returned boolean value can be used with case expression:

["case",
    condition: boolean, output: OutputType,
    condition: boolean, output: OutputType,
    ...,
    fallback: OutputType
]: OutputType

So you could make a textSize of a certain city bigger if it contained the word "york":

• New york
• York

[Chaoba]

It seems works well.

[chloekraw]

cc @mapbox/maps-ios @alexshalamov