MachMessageServer::Run()’s distinct |nonblocking| parameter is removed.
The information it formerly conveyed is now implied by the |timeout_ms|
parameter, which can accept two special values,
kMachMessageTimeoutNonblocking and kMachMessageTimeoutWaitIndefinitely.
TEST=client_test, snapshot_test, util_test
R=rsesek@chromium.org
Review URL: https://codereview.chromium.org/777993002