Currently a process ID of zero is used for the parent process. With the changes in bug 1580168 we will use the pid for the id of child processes, but the id for the parent process will still be zero --- this avoids needing to change the RDP messages used when the browser toolbox attaches to a firefox parent process. It would be nice to fix this so that the id of the parent process is also the pid, so that process IDs can be handled uniformly within the devtools.