Add additive animation support for CSS property background-position

third_party/WebKit/Source/wtf/RefVector.h

Index: third_party/WebKit/Source/wtf/RefVector.h
diff --git a/third_party/WebKit/Source/wtf/RefVector.h b/third_party/WebKit/Source/wtf/RefVector.h
index 0571fc7acf408c5a7f20a9bb001b018a932987a4..824aa44c47b07372dd7fbe057764f9d62858b552 100644
--- a/third_party/WebKit/Source/wtf/RefVector.h
+++ b/third_party/WebKit/Source/wtf/RefVector.h
@@ -15,7 +15,9 @@ template <typename T>
 class RefVector : public RefCounted<RefVector<T>> {
 public:
     static PassRefPtr<RefVector> create() { return adoptRef(new RefVector<T>); }
-    PassRefPtr<RefVector> copy() { return adoptRef(new RefVector<T>(*this)); }
+    static PassRefPtr<RefVector> create(const Vector<T>& vector) { return adoptRef(new RefVector<T>(vector)); }
+    static PassRefPtr<RefVector> create(Vector<T>&& vector) { return adoptRef(new RefVector<T>(vector)); }
+    PassRefPtr<RefVector> copy() { return create(vector()); }
 
     const T& operator[](size_t i) const { return m_vector[i]; }
     T& operator[](size_t i) { return m_vector[i]; }
@@ -33,7 +35,8 @@ public:
 private:
     Vector<T> m_vector;
     RefVector() { }
-    RefVector(const RefVector& o) : m_vector(o.m_vector) { }
+    RefVector(const Vector<T>& vector) : m_vector(vector) { }
+    RefVector(Vector<T>&& vector) : m_vector(vector) { }
 };
 
 } // namespace blink