Really cache font's xHeight.

khtml/css/css_valueimpl.cpp

@@ -1089,11 +1089,9 @@ double CSSPrimitiveValueImpl::computeLengthFloat( khtml::RenderStyle *style, int
     case CSSPrimitiveValue::CSS_EMS:
         factor = style->font().pixelSize();
         break;
-    case CSSPrimitiveValue::CSS_EXS: {
-        const QFontMetrics fm = style->fontMetrics();
-        factor = fm.xHeight();
+    case CSSPrimitiveValue::CSS_EXS:
+        factor = style->htmlFont().xHeight();
         break;
-        }
     case CSSPrimitiveValue::CSS_CHS: {
         const int zw = style->htmlFont().zeroCharWidth();
         if (zw != -1) {

khtml/rendering/font.cpp

@@ -580,6 +580,7 @@ CachedFontInstance::CachedFontInstance(CachedFontFamily* p, int sz):
     descent = fm.descent();
     height  = fm.height();
     lineSpacing = fm.lineSpacing();
+    xHeight = fm.xHeight();
 
     const QChar zeroChar((ushort)48);
     if (!fm.inFont(zeroChar)) {
@@ -609,6 +610,7 @@ void CachedFontInstance::invalidate()
     descent = fm.descent();
     height  = fm.height();
     lineSpacing = fm.lineSpacing();
+    xHeight = fm.xHeight();
 
     const QChar zeroChar((ushort)48);
     if (!fm.inFont(zeroChar)) {

khtml/rendering/font.h

@@ -82,6 +82,7 @@ public:
     int descent;
     int height;
     int lineSpacing;
+    int xHeight;
     int m_zeroCharWidth;
     mutable bool invalidated;
 
@@ -241,7 +242,7 @@ public:
     int descent() const { return cfi->descent; }
     int height() const { return cfi->height; }
     int lineSpacing() const { return cfi->lineSpacing; }
-    float xHeight() const { return cfi->fm.xHeight(); }
+    int xHeight() const { return cfi->xHeight; }
 
     // return -1 if '0' char glyph not in font
     int zeroCharWidth() const { return cfi->m_zeroCharWidth; }