Generate toCSSFooValue() for CSSAspectRatioValue, CSSBorderImageSliceValue

Source/core/css/CSSValue.cpp

Index: Source/core/css/CSSValue.cpp
diff --git a/Source/core/css/CSSValue.cpp b/Source/core/css/CSSValue.cpp
index 702590d817b250ac81221a7fbe6f284706ef1efe..c32bab76e10556a24eec72a80c65028a423ad5b6 100644
--- a/Source/core/css/CSSValue.cpp
+++ b/Source/core/css/CSSValue.cpp
@@ -340,10 +340,10 @@ void CSSValue::destroy()
 
     switch (classType()) {
     case AspectRatioClass:
-        delete static_cast<CSSAspectRatioValue*>(this);
+        delete toCSSAspectRatioValue(this);
         return;
     case BorderImageSliceClass:
-        delete static_cast<CSSBorderImageSliceValue*>(this);
+        delete toCSSBorderImageSliceValue(this);
         return;
     case CanvasClass:
         delete static_cast<CSSCanvasValue*>(this);