Shows the default_address_family on both the DNS tab and in log dumps,
and adds an extra note emphasizing when IPv6 has been disabled to both
pages.

Also adds a button to enable IPv6 when it's been disabled, and maps
address family values on the DNS tab to their symbolic names.

BUG=55007,55005
TEST=manual

Review URL: http://codereview.chromium.org/3387007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@61795 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed