Fix underline position and thickness calculation.

Source/platform/fonts/skia/SimpleFontDataSkia.cpp

Index: Source/platform/fonts/skia/SimpleFontDataSkia.cpp
===================================================================
--- Source/platform/fonts/skia/SimpleFontDataSkia.cpp	(revision 173391)
+++ Source/platform/fonts/skia/SimpleFontDataSkia.cpp	(working copy)
@@ -131,12 +131,13 @@
     m_fontMetrics.setLineGap(lineGap);
     m_fontMetrics.setLineSpacing(lroundf(ascent) + lroundf(descent) + lroundf(lineGap));
 
-    float underlineThickness = SkScalarToFloat(metrics.fUnderlineThickness);
-    m_fontMetrics.setUnderlineThickness(underlineThickness);
+    SkScalar underlineThickness, underlinePosition;
+    if (metrics.hasUnderlineThickness(&underlineThickness)
+        && metrics.hasUnderlinePosition(&underlinePosition)) {

[reed1, 2014/05/12 12:34:12]

nit: not sure you need the LF

+        m_fontMetrics.setUnderlineThickness(SkScalarToFloat(underlineThickness));
+        m_fontMetrics.setUnderlinePosition(SkScalarToFloat(-underlinePosition));
+    }
 
-    float underlinePosition = SkScalarToFloat(metrics.fUnderlinePosition);
-    m_fontMetrics.setUnderlineThickness(underlinePosition);
-
     if (platformData().orientation() == Vertical && !isTextOrientationFallback()) {
         static const uint32_t vheaTag = SkSetFourByteTag('v', 'h', 'e', 'a');
         static const uint32_t vorgTag = SkSetFourByteTag('V', 'O', 'R', 'G');