Include the outline into the visual overflow

This change makes the outline a first class visual effect instead
of being applied manually in the code. This removes the crazy fudge
factor logic that would grow *ANY* repaint rectangle by the maximal
outline on the page.

All test changes are progressions apart from 2 multi-column tests
regressing due to http://crbug.com/348064:
- fast/forms/range/slider-in-multi-column.html
- fast/forms/number/number-spinbutton-in-multi-column.html
A fix is in progress for the underlying issue that will make them
pass again (thanks to Morten Stenshome).

BUG=273904

Review URL: https://codereview.chromium.org/176953008

git-svn-id: svn://svn.chromium.org/blink/trunk@169659 bbb929c8-8fbe-4397-9dbb-9b2b20218538