Investigate possibility to bundle non-GAEN libs "transparently"

[cgrigis]

From @gannimo:

We could have a thin thin thin interposition layer. That, when initialization happens, checks if these GAEN APIs are available using reflection. If they are not available, go for our implementation.
Consider this a "nice to have" not a "must", so low priority for now I guess.
I'm curious if it's possible though.

[cgrigis]

This had partly been discussed with the microG people early on. It is however unclear whether such an app would be allowed on Google Play.

[cgrigis]

On the technical side, some pointers for dynamically loading code:

• https://developer.android.com/reference/dalvik/system/DexClassLoader
• https://github.com/artyomd/Injector

Regarding Google Play Developer Program Policy:

(...) an app may not download executable code (e.g. dex, JAR, .so files) from a source other than Google Play. (...)

Assuming the code to load dynamically would be bundled with the app, that may be allowed.