A recent change modified the way we destroy the remote renderer from
asynchronous to synchronous. This caused problems since it was possible
that the remote rendering service is unbound while we are reading the
contents of a rendered page. As a result the reader was blocking on I/O
and the print spooler was getting into a locked state that required a
restart of its process. Now the remote renderer is destroyed
asynchronously.
bug:18498626
Change-Id: I1312bf808f30430728b4038dd4be43c55d2be825
c80814e70a