Web Animations CSS: Support animation of {text,box,-webkit-box}-shadow and fix blur clamping

Source/core/animation/AnimatableValue.h

Index: Source/core/animation/AnimatableValue.h
diff --git a/Source/core/animation/AnimatableValue.h b/Source/core/animation/AnimatableValue.h
index 023b1ff4a66cdb6b7ffeb8003db8ee2af7ee928f..264c8a053ad390f76bd261faad6241c317162e6e 100644
--- a/Source/core/animation/AnimatableValue.h
+++ b/Source/core/animation/AnimatableValue.h
@@ -68,6 +68,7 @@ public:
     bool isRepeatable() const { return type() == TypeRepeatable; }
     bool isSVGLength() const { return type() == TypeSVGLength; }
     bool isSVGPaint() const { return type() == TypeSVGPaint; }
+    bool isShadow() const { return type() == TypeShadow; }
     bool isShapeValue() const { return type() == TypeShapeValue; }
     bool isStrokeDasharrayList() const { return type() == TypeStrokeDasharrayList; }
     bool isTransform() const { return type() == TypeTransform; }
@@ -100,6 +101,7 @@ protected:
         TypeRepeatable,
         TypeSVGLength,
         TypeSVGPaint,
+        TypeShadow,
         TypeShapeValue,
         TypeStrokeDasharrayList,
         TypeTransform,