Fix terminology, and include unknown and private registries when extracting Registerable Domain Names.

BUG=335902

Review URL: https://codereview.chromium.org/143943005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246569 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246569