This bug is to land the initial code for some classes reviewed in bug 1293277.

Pushed by bkelly@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/9e7aaf5d40a4 P1 Add the ClientManager class. r=baku https://hg.mozilla.org/integration/mozilla-inbound/rev/92dfd261775a P2 Add ClientManagerService and reference it from parent actors. r=baku https://hg.mozilla.org/integration/mozilla-inbound/rev/e1724fab9cbd P3 Add the ClientSource class and hook it into ClientManager/ClientManagerService. r=baku https://hg.mozilla.org/integration/mozilla-inbound/rev/63833bbedd63 P4 Add ClientHandle class and make it attach to the correct ClientSource. r=baku

https://hg.mozilla.org/mozilla-central/rev/9e7aaf5d40a4 https://hg.mozilla.org/mozilla-central/rev/92dfd261775a https://hg.mozilla.org/mozilla-central/rev/e1724fab9cbd https://hg.mozilla.org/mozilla-central/rev/63833bbedd63