Generate toCSSFooValue for CSS*GradientValues

Source/core/css/CSSValue.cpp

 /*
  * Copyright (C) 2011 Andreas Kling (kling@webkit.org)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 346 matching lines @@
     case FontFaceSrcClass:
         delete toCSSFontFaceSrcValue(this);
         return;
     case FontFeatureClass:
         delete static_cast<FontFeatureValue*>(this);
         return;
     case FunctionClass:
         delete toCSSFunctionValue(this);
         return;
     case LinearGradientClass:
-        delete static_cast<CSSLinearGradientValue*>(this);
+        delete toCSSLinearGradientValue(this);
         return;
     case RadialGradientClass:
-        delete static_cast<CSSRadialGradientValue*>(this);
+        delete toCSSRadialGradientValue(this);
         return;
     case CrossfadeClass:
         delete static_cast<CSSCrossfadeValue*>(this);
         return;
     case ImageClass:
         delete toCSSImageValue(this);
         return;
     case InheritedClass:
         delete toCSSInheritedValue(this);
         return;
@@ skipping 88 matching lines @@
         return static_cast<const SVGColor*>(this)->cloneForCSSOM();
     case SVGPaintClass:
         return static_cast<const SVGPaint*>(this)->cloneForCSSOM();
     default:
         ASSERT(!isSubtypeExposedToCSSOM());
         return TextCloneCSSValue::create(classType(), cssText());
     }
 }
 
 }