Added support of calc() for SVGLength

third_party/WebKit/Source/core/svg/SVGLength.cpp

Index: third_party/WebKit/Source/core/svg/SVGLength.cpp
diff --git a/third_party/WebKit/Source/core/svg/SVGLength.cpp b/third_party/WebKit/Source/core/svg/SVGLength.cpp
index b3c29143acc73b1f878c105add5ef1a1f7b1e6e6..cc559a15873b30a131bf77a9f403700afe6864b3 100644
--- a/third_party/WebKit/Source/core/svg/SVGLength.cpp
+++ b/third_party/WebKit/Source/core/svg/SVGLength.cpp
@@ -73,10 +73,18 @@ bool SVGLength::operator==(const SVGLength& other) const
 
 float SVGLength::value(const SVGLengthContext& context) const
 {
+    if (isCalculated())
+        return context.resolveValue(*asCSSPrimitiveValue(), unitMode());
+
     return context.convertValueToUserUnits(
         m_value->getFloatValue(), unitMode(), m_value->typeWithCalcResolved());
 }
 
+void SVGLength::setValueAsNumber(float value)
+{
+    m_value = CSSPrimitiveValue::create(value, CSSPrimitiveValue::UnitType::UserUnits);
+}
+
 void SVGLength::setValue(float value, const SVGLengthContext& context)
 {
     m_value = CSSPrimitiveValue::create(
@@ -84,9 +92,15 @@ void SVGLength::setValue(float value, const SVGLengthContext& context)
         m_value->typeWithCalcResolved());
 }
 
-bool isSupportedCSSUnitType(CSSPrimitiveValue::UnitType type)
+static bool isCalcCSSUnitType(CSSPrimitiveValue::UnitType type)
 {
-    return (CSSPrimitiveValue::isLength(type) || type == CSSPrimitiveValue::UnitType::Number || type == CSSPrimitiveValue::UnitType::Percentage)
+    return type >= CSSPrimitiveValue::UnitType::Calc && type <= CSSPrimitiveValue::UnitType::CalcPercentageWithLengthAndNumber;
+}
+
+static bool isSupportedCSSUnitType(CSSPrimitiveValue::UnitType type)
+{
+    return (CSSPrimitiveValue::isLength(type) || type == CSSPrimitiveValue::UnitType::Number
+        || type == CSSPrimitiveValue::UnitType::Percentage || isCalcCSSUnitType(type))
         && type != CSSPrimitiveValue::UnitType::QuirkyEms;
 }
 
@@ -139,8 +153,7 @@ SVGParsingError SVGLength::setValueAsString(const String& string)
         return SVGParseStatus::ExpectedLength;
 
     const CSSPrimitiveValue* newValue = toCSSPrimitiveValue(parsed);
-    // TODO(fs): Enable calc for SVG lengths
-    if (newValue->isCalculated() || !isSupportedCSSUnitType(newValue->typeWithCalcResolved()))
+    if (!isSupportedCSSUnitType(newValue->typeWithCalcResolved()))
         return SVGParseStatus::ExpectedLength;
 
     m_value = newValue;
@@ -246,7 +259,15 @@ void SVGLength::calculateAnimatedValue(SVGAnimationElement* animationElement,
 
     ASSERT(unitMode() == lengthModeForAnimatedLengthAttribute(animationElement->attributeName()));
 
-    CSSPrimitiveValue::UnitType newUnit = percentage < 0.5 ? fromLength->typeWithCalcResolved() : toLength->typeWithCalcResolved();
+    // TODO(shanmuga.m): Construct a calc() expression if the units fall in different categories.
+    CSSPrimitiveValue::UnitType newUnit = CSSPrimitiveValue::UnitType::UserUnits;
+    if (percentage < 0.5) {
+        if (!fromLength->isCalculated())
+            newUnit = fromLength->typeWithCalcResolved();
+    } else {
+        if (!toLength->isCalculated())
+            newUnit = toLength->typeWithCalcResolved();
+    }
     animatedNumber = lengthContext.convertValueFromUserUnits(animatedNumber, unitMode(), newUnit);
     m_value = CSSPrimitiveValue::create(animatedNumber, newUnit);
 }