Bug 1074735 pt 1 - Use more sensible values for underline and strikeout position in vertical font metrics. r=smontagu

gfx/thebes/gfxFont.cpp

@@ -3431,11 +3431,10 @@ gfxFont::CreateVerticalMetrics()
     // We synthesize our own positions, as font metrics don't provide these
     // for vertical layout.
     metrics->underlineSize = std::max(1.0, metrics->underlineSize);
-    metrics->underlineOffset = 0; // XXX to be adjusted
+    metrics->underlineOffset = - metrics->maxDescent - metrics->underlineSize;
 
     metrics->strikeoutSize = std::max(1.0, metrics->strikeoutSize);
-    metrics->strikeoutOffset =
-        metrics->maxDescent - 0.5 * metrics->strikeoutSize;
+    metrics->strikeoutOffset = - 0.5 * metrics->strikeoutSize;
 
     // Somewhat arbitrary values for now, subject to future refinement...
     metrics->spaceWidth = metrics->aveCharWidth;