DEPS.xwalk: Roll chromium to 881367bf.

Get the glib mainloop compiled for Ozone builds so we can
use it in the following patch.
[Extensions] Force the GLib main-loop on Linux platform

Many Linux external extensions depends on glib mainloop integration,
mainly for DBus. GLib is the default main loop on Linux Desktop, but
when building if Ozone, you get a Libevent mainloop. This patch
brings GLib back to extension process (only) when building Ozone.

Should not affect anything when building with X11 support.

BUG=XWALK-1331