Make style building for 'font-size' less custom.

Source/core/css/resolver/StyleBuilderConverter.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 88 matching lines @@
     CSSValueList* list = toCSSValueList(value);
     RefPtr<FontFeatureSettings> settings = FontFeatureSettings::create();
     int len = list->length();
     for (int i = 0; i < len; ++i) {
         CSSFontFeatureValue* feature = toCSSFontFeatureValue(list->item(i));
         settings->append(FontFeature(feature->tag(), feature->value()));
     }
     return settings;
 }
 
+class RedirectSetHasViewportUnits {
+public:
+    RedirectSetHasViewportUnits(RenderStyle* from, RenderStyle* to)
+        : m_from(from), m_to(to), m_hadViewportUnits(from->hasViewportUnits())
+    {
+        from->setHasViewportUnits(false);
+    }
+    ~RedirectSetHasViewportUnits()
+    {
+        m_to->setHasViewportUnits(m_from->hasViewportUnits());
+        m_from->setHasViewportUnits(m_hadViewportUnits);
+    }
+private:
+    RenderStyle* m_from;
+    RenderStyle* m_to;
+    bool m_hadViewportUnits;
+};
+
+static float computeFontSize(StyleResolverState& state, CSSPrimitiveValue* primitiveValue, const FontDescription::Size& parentSize)
+{
+    RedirectSetHasViewportUnits redirect(state.parentStyle(), state.style());
+
+    CSSToLengthConversionData conversionData(state.parentStyle(), state.rootElementStyle(), state.document().renderView(), 1.0f, true);
+    if (primitiveValue->isLength())
+        return primitiveValue->computeLength<float>(conversionData);
+    if (primitiveValue->isCalculatedPercentageWithLength())
+        return primitiveValue->cssCalcValue()->toCalcValue(conversionData)->evaluate(parentSize.value);
+
+    ASSERT_NOT_REACHED();
+    return 0;
+}
+
+FontDescription::Size StyleBuilderConverter::convertFontSize(StyleResolverState& state, CSSValue* value)
+{
+    CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
+
+    FontDescription::Size parentSize(0, 0.0f, false);
+
+    // FIXME: Find out when parentStyle could be 0?
+    if (state.parentStyle())
+        parentSize = state.parentFontDescription().size();
+
+    if (CSSValueID valueID = primitiveValue->getValueID()) {
+        switch (valueID) {
+        case CSSValueXxSmall:
+        case CSSValueXSmall:
+        case CSSValueSmall:
+        case CSSValueMedium:
+        case CSSValueLarge:
+        case CSSValueXLarge:
+        case CSSValueXxLarge:
+        case CSSValueWebkitXxxLarge:
+            return FontDescription::Size(FontSize::keywordSize(valueID), 0.0f, false);
+        case CSSValueLarger:
+            return FontDescription::largerSize(parentSize);
+        case CSSValueSmaller:
+            return FontDescription::smallerSize(parentSize);
+        default:
+            ASSERT_NOT_REACHED();
+            return FontBuilder::initialSize();
+        }
+    }
+
+    if (primitiveValue->isPercentage())
+        return FontDescription::Size(0, (primitiveValue->getFloatValue() * parentSize.value / 100.0f), false);
+
+    return FontDescription::Size(0, computeFontSize(state, primitiveValue, parentSize), !primitiveValue->isFontRelativeLength());
+}
+
 FontWeight StyleBuilderConverter::convertFontWeight(StyleResolverState& state, CSSValue* value)
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
     switch (primitiveValue->getValueID()) {
     case CSSValueBolder:
         return FontDescription::bolderWeight(state.parentStyle()->fontDescription().weight());
     case CSSValueLighter:
         return FontDescription::lighterWeight(state.parentStyle()->fontDescription().weight());
     default:
         return *primitiveValue;
@@ skipping 406 matching lines @@
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue->getValueID()) {
         float multiplier = convertLineWidth<float>(state, value);
         return CSSPrimitiveValue::create(multiplier / 48, CSSPrimitiveValue::CSS_EMS)->computeLength<float>(state.cssToLengthConversionData());
     }
     return primitiveValue->computeLength<float>(state.cssToLengthConversionData());
 }
 
 } // namespace blink