Style JSON String support

[tobrun]

Feature request to support loading a style json from a string. After digging some through the documentation here, I'm not seeing how I can load a string to be the rendered style. Am I missing something? I believe this is a very useful API to support.

cc @julianrex

[julianrex]

@tobrun can you point me at the Android equivalent please?

[tobrun]

Public API binding in https://github.com/mapbox/mapbox-gl-native/blob/master/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMap.java#L798.
Which uses this builder https://github.com/mapbox/mapbox-gl-native/blob/master/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Style.java#L595
Which hooks into the core map api: https://github.com/mapbox/mapbox-gl-native/blob/master/src/mbgl/style/style.cpp#L17

[1ec5]

This is a duplicate of #6386, right?

[1ec5]

Closing in favor of #6386.