Remove special cases for viewport units, and add tests for viewport units in calc().

Source/core/animation/AnimatableLength.h

Index: Source/core/animation/AnimatableLength.h
diff --git a/Source/core/animation/AnimatableLength.h b/Source/core/animation/AnimatableLength.h
index d45bb365cb2f96d4688f2e4088b85645a39853ab..90e40a3c78ee8d1c2e8f7ff879082b6b4821fd2e 100644
--- a/Source/core/animation/AnimatableLength.h
+++ b/Source/core/animation/AnimatableLength.h
@@ -67,7 +67,6 @@ public:
 protected:
     virtual PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const OVERRIDE;
     virtual PassRefPtrWillBeRawPtr<AnimatableValue> addWith(const AnimatableValue*) const OVERRIDE;
-    virtual bool usesDefaultInterpolationWith(const AnimatableValue*) const OVERRIDE;
 
 private:
     AnimatableLength(double number, CSSPrimitiveValue::LengthUnitType unitType, CSSPrimitiveValue* cssPrimitiveValue)
@@ -91,14 +90,6 @@ private:
     static bool isCalc(CSSPrimitiveValue::LengthUnitType type) { return type == CSSPrimitiveValue::UnitTypeCalc; }
     bool isCalc() const { return isCalc(m_lengthUnitType); }
 
-    bool isViewportUnit() const
-    {
-        return m_lengthUnitType == CSSPrimitiveValue::UnitTypeViewportWidth
-            || m_lengthUnitType == CSSPrimitiveValue::UnitTypeViewportHeight
-            || m_lengthUnitType == CSSPrimitiveValue::UnitTypeViewportMin
-            || m_lengthUnitType == CSSPrimitiveValue::UnitTypeViewportMax;
-    }
-
     static PassRefPtrWillBeRawPtr<AnimatableLength> create(const AnimatableLength* leftAddend, const AnimatableLength* rightAddend)
     {
         ASSERT(leftAddend && rightAddend);