04e3dfee76
We currently use ipc::FileDescriptor which is implicitly copyable, and as a result we end up inadvertently duping the file descriptors in a few places. This patch switches to UniqueFileHandle which makes cloning explicit. This uncovers a few places where we were accidentally copying the file descriptor, which this patch also fixes. Differential Revision: https://phabricator.services.mozilla.com/D238595