Refactor applypatch/main.cpp into libapplypatch_modes so that we can add
testcases.
Some changes to applypatch/main.cpp:
- Replace char** argv with const char**;
- Use android::base::Split() to split ":";
- Use android::base::ParseUInt().
Bug: 32383590
Test: Unit tests pass, install-recovery.sh works.
Change-Id: I44e7bfa5ab717d439ea1d0ee9ddb7b2c40bb95a4