The patch for bug 946407 changed the state space of
nsMemoryReporterManager in a subtle way: if we're using
MinimizeMemoryUsage with our report, then it's possible for all of
the child processes to finish (or for the timeout to expire) before
the parent has started reporting on itself. This could cause us to
dereference a null pointer to the state struct in StartGettingReports().
To fix this, we keep track of whether the parent has actually done its
report, and defer finishing the report until then.
3b4495d665