This cl ensures at most 1 instance of edit monitor running from the
same binary by killing any existing instance before starting.
Specifically, When an edit monitor process starts, it will write a pidfile containing its pid and if such pidfile already exists (which means there's another instance there), it will read the pid contained in that pidfile and kill the corresponding process first.
Test: atst daemon_manager_test
bug: 365617369
Change-Id: I76954344df649aa79a6ef07ce55a62985decdb53
Creates a class that will manager and monitor the actual edit watchdog
that run as a subprocess. As a first step, the class supports:
1) A start method that creates a pidfile and starts a subprocess with given target/args.
2) A stop method that terminates the created subprocess and removes the pidfile.
Detailed design in go/android-local-edit-monitor.
Test: atest daemon_manager_test
bug: 365617369
Change-Id: Ic6d7be67d284ade8033416235b9b0fb1e90e1b1a
