Introduce Node::containingTreeScope(), which asserts that the node's root is a tree scope

third_party/WebKit/Source/core/dom/Node.cpp

Index: third_party/WebKit/Source/core/dom/Node.cpp
diff --git a/third_party/WebKit/Source/core/dom/Node.cpp b/third_party/WebKit/Source/core/dom/Node.cpp
index 7ff26433da8eeb4b6d0e1727615d10484e84f811..17eaad9dc04497c021e6f75af3b8038b26e576b9 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -373,7 +373,7 @@ Node* Node::pseudoAwareLastChild() const
 Node& Node::treeRoot() const
 {
     if (isInTreeScope())
-        return treeScope().rootNode();
+        return rootTreeScope().rootNode();
     const Node* node = this;
     while (node->parentNode())
         node = node->parentNode();