services: fix START_STICKY

[mzakharo]

This patchet is fixing a Java stack-trace during a restart of sticky service by the OS.

Specifically:
E AndroidRuntime: Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Bundle android.content.Intent.getExtras()' on a null object reference

To reproduce, one can force a system memory pressure event by allocating a bunch of ram in another process.

Sticky background services + ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS allows for creating resilient background services that get auto-restarted by Android OS under memory/resource pressure, and thus can outlast normal services created using the official auto-restart documentation

This patchset is inspired by this stackoverflow post

[AndreMiras]

Thanks for investigating and fixing. I left few comments/questions, but I think we're already close to getting something we can merge.
Another path that might be worth investigating is the START_REDELIVER_INTENT bit.
If I understood correctly, it may behave like the START_STICKY, but providing the intent this time. That would make the diff much shorter as just changing START_STICKY to START_REDELIVER_INTENT. That's something to investigate

[AndreMiras]

Thanks for the clean up and the feedback on the comments.
I think we're OK. I'll leave it there a few days before merging in case someone (@inclement?) has something to say.
This part of the code is not heavily used, nor tested, it has few edge cases that're easy to overlook

[mzakharo]

Turns out there are usecases where both foreground + STICKY is useful, in which case, the original CL was inusfficient.

latest CL addresses the foreground service support, ads a comment for why we dont turn off sticky services on app termination.

Also, this adds a new getDefaultIntet method, which removes logic duplication while starting a service from a custom broadcast receiver.

        ix = ServiceMycustomservice.getDefaultIntent(context, "");
        ix.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startService(ix);

[mzakharo]

Can someone please review this PR?

[AndreMiras]

Thanks for updating with latest develop change. I usually prefer a rebase tho.
I will squash & merge