Move rootUserSelectAllForNode() to EditingStrategy template class from PositionAlgorithm template cl

Source/core/editing/EditingStrategy.h

Index: Source/core/editing/EditingStrategy.h
diff --git a/Source/core/editing/EditingStrategy.h b/Source/core/editing/EditingStrategy.h
index b0d9d62fd1ee9cde42922c47aa181d34012a2c0f..ab03db4333625ba7c12b542a5d2808f41e1110cd 100644
--- a/Source/core/editing/EditingStrategy.h
+++ b/Source/core/editing/EditingStrategy.h
@@ -33,6 +33,7 @@ public:
     // Positions. Be sure to call |parentAnchoredEquivalent()| on a Position
     // before using it to create a DOM Range, or an exception will be thrown.
     static int lastOffsetForEditing(const Node*);
+    static Node* rootUserSelectAllForNode(Node*);
 };
 
 extern template class CORE_EXTERN_TEMPLATE_EXPORT EditingAlgorithm<NodeTraversal>;