[PrintPreview] Custom input focus toggles
In print preview mode, focus toggles for radio buttons for pagerange
settings when custom input radio button is clicked again and page
range is empty.
This is not desired and happens because focus is set for
another radio button on blur event for custom input radio
button when it is empty.
BUG=397094
Review URL: https://codereview.chromium.org/
435393005
Cr-Commit-Position: refs/heads/master@{#288485}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288485 0039d316-1c4b-4281-b951-d872f2087c98