SocketsManifestPermission bug fix.

* ToValue() didn't work with multiple entries because of an overzealous "break" statement.

Also, remove |kinds_| member: it is not really necessary since we can't (and don't need to)
guarantee 100% round trip, and this was making code more complex than needed.

Also updated unit tests to cover bug fix.

BUG=165273
BUG=173241

Review URL: https://codereview.chromium.org/81943002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236706 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236706