[REGRESSION] Button cannot be clicked with text-indent : -99999999px after r143483.

Merged from http://trac.webkit.org/changeset/155546. 
This caused a bad repaint regression, when authors combine negative text-indent with overflow:hidden 
(which is what we recommend they do): bug 121137.
Revert the change, and add a new test to make sure it doesn't regress.

BUG=321892
TEST=
fast/repaint/negative-text-indent-with-overflow-hidden.html
fast/events/click-with-large-negative-text-indent.html
fast/repaint/paint-caret-in-div-with-negative-indent.html

Review URL: https://codereview.chromium.org/81833005

git-svn-id: svn://svn.chromium.org/blink/trunk@162590 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[CSS Regions] Use hasOverflowClip() in RenderRegion

Patch already landed in WebKit. See http://trac.webkit.org/changeset/159682

Implement the suggested FIXME in RenderRegion using hasOverflowClip().

Review URL: https://codereview.chromium.org/83273002

git-svn-id: svn://svn.chromium.org/blink/trunk@162591 bbb929c8-8fbe-4397-9dbb-9b2b20218538