Make sure that command line arguments overrides our defaults for features.

Brave developers who want to switch on or off some of our features
can do so using the command line arguments and it will override
what XWalk sets as its default.

Inside Crosswalk we're supposed to use the static methods of
XWalkRuntimeEnabledFeatures to test if a feature is on or off.
Protect the SysApp RawSocket API behind a feature flag.

The flag is ON by default.