text-decoration-skip: ink skips randomly when using SVG fonts

text-decoration-skip: ink skips randomly when using SVG fonts
https://bugs.webkit.org/show_bug.cgi?id=128709

Reviewed by Simon Fraser.

Source/WebCore:

This patch simply disables skipping underlines being used with SVG fonts.
It's a stopgap until we can support skipping properly with SVG fonts.

Test: svg/custom/svg-fonts-skip-ink.html

* platform/graphics/cocoa/FontPlatformDataCocoa.mm:
(WebCore::FontPlatformData::ctFont):
* platform/graphics/mac/FontMac.mm:
(WebCore::Font::dashesForIntersectionsWithRect):

LayoutTests:

This text checks that some text without descenders in an SVG font renders the same with and
without text-decoration-skip: ink.

* svg/custom/svg-fonts-skip-ink-expected.html: Added.
* svg/custom/svg-fonts-skip-ink.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@164075 268f45cc-cd09-0410-ab3c-d52691b4dbfc