Preliminary port of QuicServer

Ported QuicServer to the Chromium network stack, keeping it in net_unittests for now so that it does not bloat the main build. Some of the changes:
* used QuicConnectionHelper to manage alarms
* used asynchronous callbacks rather than a nonblocking I/O loop
* used UDPServerSocket rather than fds
* pulled in a bunch of dependencies, some of which will have to be removed again.

BUG=

Review URL: https://codereview.chromium.org/322653002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@277606 0039d316-1c4b-4281-b951-d872f2087c98
18 files changed