Decouple font unit conversion in computeLengthDouble from RenderStyle.

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 171 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());
+    float em = state.parentStyle()->specifiedFontSize();
+    float rem = state.rootElementStyle() ? state.rootElementStyle()->specifiedFontSize() : 1.0f;
+    CSSToLengthConversionData::FontSizes fontSizes(em, rem, &state.parentStyle()->font());
+    CSSToLengthConversionData::ViewportSize viewportSize(state.document().renderView());
 
-    CSSToLengthConversionData conversionData(state.parentStyle(), state.rootElementStyle(), state.document().renderView(), 1.0f, true);
+    CSSToLengthConversionData conversionData(state.style(), fontSizes, viewportSize, 1.0f);
     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)
@@ skipping 594 matching lines @@
     CSSPrimitiveValue* primitiveValueZ = toCSSPrimitiveValue(list->item(2));
 
     return TransformOrigin(
         convertOriginLength<CSSValueLeft, CSSValueRight>(state, primitiveValueX),
         convertOriginLength<CSSValueTop, CSSValueBottom>(state, primitiveValueY),
         StyleBuilderConverter::convertComputedLength<float>(state, primitiveValueZ)
     );
 }
 
 } // namespace blink