Textarea resize-able only to larger; min-height and min-width properly set

Textarea does not respect the min-height and min-width property when they are
set by user. When textarea min-height and min-width is set by the user and
if we resize textarea it will only resize to value larger than the width and
heght of textarea and not with value smaller than it's width and height. It
assumes width and height as min-width and min height and does not take into
account the actual min-width and min-height set by user. This patch removes
this bug by initializing the setMinimumSizeForResizing value with min-width
and min-height.

BUG=94583

Review URL: https://codereview.chromium.org/239983004

git-svn-id: svn://svn.chromium.org/blink/trunk@173269 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Avoid noise caused by scrollbar fast/repaint/border-radius-repaint-2.html

Noticed this during repaint optimization work. The original repaints were
actually caused by the change of scrollbar existence, not the repaints
the test wanted to test.

Use overlay scrollbars to avoid the noise.

Review URL: https://codereview.chromium.org/268623014

git-svn-id: svn://svn.chromium.org/blink/trunk@173270 bbb929c8-8fbe-4397-9dbb-9b2b20218538