Revert 225303 "Added NetworkInterface::network_prefix."

> Added NetworkInterface::network_prefix.
> 
> BUG=295997
> NOTRY=true
> 
> Review URL: https://codereview.chromium.org/23726043

TBR=vitalybuka@chromium.org

Review URL: https://codereview.chromium.org/24530007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225326 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225326