calc expressions should support time, angle and frequency values.

Source/core/css/CSSPrimitiveValue.h

Index: Source/core/css/CSSPrimitiveValue.h
diff --git a/Source/core/css/CSSPrimitiveValue.h b/Source/core/css/CSSPrimitiveValue.h
index 76846ab687dc2594d74dc633f276f7ae97ceb738..516e96e0f45413ef4438b7e85dbdf7a4f31abc37 100644
--- a/Source/core/css/CSSPrimitiveValue.h
+++ b/Source/core/css/CSSPrimitiveValue.h
@@ -270,24 +270,12 @@ public:
 
     void cleanup();
 
+    enum TimeUnit { Seconds, Milliseconds };
     UnitType primitiveType() const;
+    UnitType calcUnitType() const;
 
     double computeDegrees();
-
-    enum TimeUnit { Seconds, Milliseconds };
-    template <typename T, TimeUnit timeUnit> T computeTime()
-    {
-        if (timeUnit == Seconds && m_primitiveUnitType == CSS_S)
-            return getValue<T>();
-        if (timeUnit == Seconds && m_primitiveUnitType == CSS_MS)
-            return getValue<T>() / 1000;
-        if (timeUnit == Milliseconds && m_primitiveUnitType == CSS_MS)
-            return getValue<T>();
-        if (timeUnit == Milliseconds && m_primitiveUnitType == CSS_S)
-            return getValue<T>() * 1000;
-        ASSERT_NOT_REACHED();
-        return 0;
-    }
+    double computeSeconds();
 
     /*
      * Computes a length in pixels out of the given CSSValue