The new 3rdparty submodule contains snapshots of both ninja
and chromium. This drastically reduces the size of the repository
and can be used by our CI system.

Change-Id: Ie7482181f2ba9dba5fc181b1f221a5fae714c8c8
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>
Reviewed-by: Zeno Albisser <zeno.albisser@digia.com>