Move instead of clone shadow tree children

Source/core/svg/SVGUseElement.cpp

Index: Source/core/svg/SVGUseElement.cpp
diff --git a/Source/core/svg/SVGUseElement.cpp b/Source/core/svg/SVGUseElement.cpp
index cdb277c033d1fc467a8d29f2b34f37f3188f3baa..8a8a1d6c16ef63805a0f77bb36f1b581611683fb 100644
--- a/Source/core/svg/SVGUseElement.cpp
+++ b/Source/core/svg/SVGUseElement.cpp
@@ -650,7 +650,11 @@ void SVGUseElement::expandUseElementsInShadowTree(Node* element)
         // Don't ASSERT(target) here, it may be "pending", too.
         // Setup sub-shadow tree root node
         RefPtr<SVGGElement> cloneParent = SVGGElement::create(referencedScope()->document());
-        use->cloneChildNodes(cloneParent.get());
+        for (Node* child = use->firstChild(); child;) {
+            Node* oldChild = child;
+            child = child->nextSibling();
+            cloneParent->appendChild(oldChild);
+        }
 
         // Spec: In the generated content, the 'use' will be replaced by 'g', where all attributes from the
         // 'use' element except for x, y, width, height and xlink:href are transferred to the generated 'g' element.
@@ -705,9 +709,10 @@ void SVGUseElement::expandSymbolElementsInShadowTree(Node* element)
         svgElement->cloneDataFromElement(*toElement(element));
 
         // Only clone symbol children, and add them to the new <svg> element
-        for (Node* child = element->firstChild(); child; child = child->nextSibling()) {
-            RefPtr<Node> newChild = child->cloneNode(true);
-            svgElement->appendChild(newChild.release());
+        for (Node* child = toSVGElement(element)->firstChild(); child;) {
+            Node* oldChild = child;
+            child = child->nextSibling();
+            svgElement->appendChild(oldChild);
         }
 
         // We don't walk the target tree element-by-element, and clone each element,