Try OkHTTP on Android again

[ljbade]

Time to try #2033 again and use OkHTTP instead of curl for Android.

Previous blocker for this was #2400 which has not been looked at for a while.

Things that might have fixed that crash:

• updating libuv - Update libuv to 1.7.5 #2609
• refactor in the core GL HTTP code - Request again when obtained data expires #2617

OkHTTP will be an enabler for offline support.

/cc @bleege @tobrun

[ljbade]

We will need to perform extended testing over a period of time as #2400 was a rare and hard to reproduce reliably.

Perhaps a Sirius build with this change included will provide the confidence needed.

[ljbade]

Simply switching config.mk to the Android HTTP implementation, reveals bit rot in http_request_android.cpp due to refactors.

[mb12]

@ljbade The only advantage of this is reduced .apk size. Its no longer an issue on Android (since apk size limit has been doubled). Why do we want to change this if curl implementation does not have any bugs?

[ljbade]

After fixing the compile errors, the OkHTTP stack is working again. So far I have not been able to reproduce #2400 but more testing is needed.

[bleege]

Why do we want to change this if curl implementation does not have any bugs?

@mb12 The big reason is as you mentioned, a reduced .aar and .apk sizes. Not having to compile it for N ABI really helps keep things svelte. Another reason is to use more platform specific implementations (in this case Java for Android) as it is more accessible to developers.

[bleege]

For future reference, by replacing curl with OkHttp the Mapbox Android Library .aar file goes from ~11 MB to ~7.8 MB.

Mapbox Android SDK 2.2.0 with curl

Mapbox Android SDK 2.3.0-SNAPSHOT with OkHttp replacing curl

The size of OkHttp and it's dependency Okio combine to be about ~375 KB so that the net result is a ~2.825 MB overall decrease in size by replacing curl with OkHttp.

OkHttp Library

Okio Library