Generate toCSSFooValue() for CSSCanvasValue, CSSCrossfadeValue, CSSImageGeneratorValue, CSSImageVal…

Source/core/css/CSSTimingFunctionValue.h

Index: Source/core/css/CSSTimingFunctionValue.h
diff --git a/Source/core/css/CSSTimingFunctionValue.h b/Source/core/css/CSSTimingFunctionValue.h
index 87f2b7ad94344702b4193ef3bcf225299751ab61..3f81d6a0bfe0c4891ebb882be47e8fdad9037f96 100644
--- a/Source/core/css/CSSTimingFunctionValue.h
+++ b/Source/core/css/CSSTimingFunctionValue.h
@@ -63,6 +63,8 @@ private:
     double m_y2;
 };
 
+DEFINE_CSS_VALUE_TYPE_CASTS(CubicBezierTimingFunctionValue);
+
 class CSSStepsTimingFunctionValue : public CSSValue {
 public:
     static PassRefPtr<CSSStepsTimingFunctionValue> create(int steps, bool stepAtStart)
@@ -89,6 +91,8 @@ private:
     bool m_stepAtStart;
 };
 
+DEFINE_CSS_VALUE_TYPE_CASTS(StepsTimingFunctionValue);
+
 } // namespace
 
 #endif