chromium: Update dev channel to v30.0.1568.0.

The sha256 has changed upstream for 30.0.1566.2 and in addition there is
a new version available, so let's switch to the new version.

Unfortunately the user namespaces sandbox patch doesn't apply anymore
because of http://crbug.com/242290, so this adds a rebased version on
top of the current trunk of Chromium.

In order to build version 30, file is now needed as an additional build
input, because it is used by gyp.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>