Web Animations CSS: Support animation of stroke-dasharray property

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 adc85162ff9613e942b555f3ab15896b4a0f6264..6e82eb43ce39069f0568c3946477e56f957c8f2e 100644
--- a/Source/core/animation/AnimatableValue.h
+++ b/Source/core/animation/AnimatableValue.h
@@ -60,6 +60,7 @@ public:
     bool isLengthSize() const { return type() == TypeLengthSize; }
     bool isNeutral() const { return type() == TypeNeutral; }
     bool isSVGLength() const { return type() == TypeSVGLength; }
+    bool isSVGLengthVector() const { return type() == TypeSVGLengthVector; }
     bool isShapeValue() const { return type() == TypeShapeValue; }
     bool isSVGPaint() const { return type() == TypeSVGPaint; }
     bool isTransform() const { return type() == TypeTransform; }
@@ -77,6 +78,7 @@ protected:
         TypeLengthSize,
         TypeNeutral,
         TypeSVGLength,
+        TypeSVGLengthVector,
         TypeShapeValue,
         TypeSVGPaint,
         TypeTransform,