Narrow underlines are too tall

Narrow underlines are too tall
https://bugs.webkit.org/show_bug.cgi?id=126708

Reviewed by Simon Fraser.

Source/WebCore:

I made a typo in r158392 and used was settings the line rect's
height equal to its width. No one noticed because of the subsequent
if statement.

Test: fast/css3-text/css3-text-decoration/text-decoration-skip/text-decoration-skip-tall-underlines.html

* platform/graphics/cg/GraphicsContextCG.cpp:
(WebCore::computeLineBoundsAndAntialiasingModeForText):

LayoutTests:

This test clips to a region that should not be drawn in, then draws a scaled underline. It then compares
the output to an empty element.

* fast/css3-text/css3-text-decoration/text-decoration-skip/text-decoration-skip-tall-underlines-expected.html: Added.
* fast/css3-text/css3-text-decoration/text-decoration-skip/text-decoration-skip-tall-underlines.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@161573 268f45cc-cd09-0410-ab3c-d52691b4dbfc