[Qt] Implement SimpleFontData::platformBoundsForGlyph
https://bugs.webkit.org/show_bug.cgi?id=104127

Reviewed by Jocelyn Turcotte.

Implements platformBoundsForGlyph which is necessary for working MathML and Ruby.

* platform/graphics/qt/SimpleFontDataQt.cpp:
(WebCore::SimpleFontData::platformBoundsForGlyph):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@138703 268f45cc-cd09-0410-ab3c-d52691b4dbfc