Move viewport unit resolution to style recalc time

Source/core/css/resolver/FontBuilder.cpp

Index: Source/core/css/resolver/FontBuilder.cpp
diff --git a/Source/core/css/resolver/FontBuilder.cpp b/Source/core/css/resolver/FontBuilder.cpp
index 115419690518dec1c0df56a131d0f964fc643a2f..f7ea2a79a3cdd6be322ae2c9f7ff7668302e95a7 100644
--- a/Source/core/css/resolver/FontBuilder.cpp
+++ b/Source/core/css/resolver/FontBuilder.cpp
@@ -62,6 +62,7 @@ private:
 FontBuilder::FontBuilder()
     : m_document(0)
     , m_useSVGZoomRules(false)
+    , m_fontSizehasViewportUnits(false)
     , m_fontDirty(false)
 {
 }
@@ -324,16 +325,22 @@ void FontBuilder::setFontSizeValue(CSSValue* value, RenderStyle* parentStyle, co
         scope.fontDescription().setIsAbsoluteSize(parentIsAbsoluteSize && (valueID == CSSValueLarger || valueID == CSSValueSmaller));
     } else {
         scope.fontDescription().setIsAbsoluteSize(parentIsAbsoluteSize || !(primitiveValue->isPercentage() || primitiveValue->isFontRelativeLength()));
-        if (primitiveValue->isLength())
-            size = primitiveValue->computeLength<float>(CSSToLengthConversionData(parentStyle, rootElementStyle, 1.0, true));
-        else if (primitiveValue->isPercentage())
+        if (primitiveValue->isPercentage()) {
             size = (primitiveValue->getFloatValue() * parentSize) / 100.0f;
-        else if (primitiveValue->isCalculatedPercentageWithLength())
-            size = primitiveValue->cssCalcValue()->toCalcValue(CSSToLengthConversionData(parentStyle, rootElementStyle, 1.0f))->evaluate(parentSize);
-        else if (primitiveValue->isViewportPercentageLength())
-            size = valueForLength(primitiveValue->viewportPercentageLength(), 0, m_document->renderView());
-        else
-            return;
+        } else {
+            // If we have viewport units the conversion will mark the parent style as having viewport units.
+            bool parentHasViewportUnits = parentStyle->hasViewportUnits();
+            parentStyle->setHasViewportUnits(false);

[esprehn, 2013/12/04 06:02:28]

Why do you need to disable the viewport units flag here and then re-enable it
later?

[Timothy Loh, 2013/12/04 07:17:39]

This is one of the few places where we resolve viewport units where ems don't
refer to the current style. The conversion will set the bit on the parent style
and this works around it.

+            CSSToLengthConversionData conversionData(parentStyle, rootElementStyle, m_document->renderView(), 1.0f, true);
+            if (primitiveValue->isLength())
+                size = primitiveValue->computeLength<float>(conversionData);
+            else if (primitiveValue->isCalculatedPercentageWithLength())
+                size = primitiveValue->cssCalcValue()->toCalcValue(conversionData)->evaluate(parentSize);
+            else
+                ASSERT_NOT_REACHED();
+            m_fontSizehasViewportUnits = parentStyle->hasViewportUnits();
+            parentStyle->setHasViewportUnits(parentHasViewportUnits);
+        }
     }
 
     if (size < 0)