Change EllipsisBox::paint to use TextPainter.

This not only simplifies it, but it becomes more consistent with the usual text
style. In particular, ellipsis boxes gain print color adjustment (so white
ellipsis no longer disappears) and text strokes, when the style asks for them.

Two layout tests are added to demonstrate this. These fail without this patch.

The performance impact of moving textPaintingStyle to TextPainter.cpp seems
negligible.

BUG=241073

Review URL: https://codereview.chromium.org/586713002

git-svn-id: svn://svn.chromium.org/blink/trunk@182415 bbb929c8-8fbe-4397-9dbb-9b2b20218538