Move non-navigation URL handlers to HandleNonNavigationAboutURL

R=sky
BUG=271324

Review URL: https://codereview.chromium.org/105203002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238957 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238957