WIP (Introduce WTF::NonNullPtr<T>.)

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index 0e3d2cb0e0128ad9d41ed42a2eb9dfc42a453c71..1d62f6a3bd5c6240506f11f6ab2dea17170c3ffe 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -910,7 +910,7 @@ bool Node::isDescendantOf(const Node *other) const
     // Return true if other is an ancestor of this, otherwise false
     if (!other || !other->hasChildNodes() || inDocument() != other->inDocument())
         return false;
-    if (&other->treeScope() != &treeScope())
+    if (other->treeScope() != treeScope())
         return false;
     if (other->isTreeScope())
         return !isTreeScope();
@@ -948,7 +948,7 @@ bool Node::containsIncludingShadowDOM(const Node* node) const
         return false;
 
     for (; node; node = node->shadowHost()) {
-        if (&treeScope() == &node->treeScope())
+        if (treeScope() == node->treeScope())
             return contains(node);
     }
 
@@ -1159,7 +1159,7 @@ Node* Node::deprecatedShadowAncestorNode() const
 
 ShadowRoot* Node::containingShadowRoot() const
 {
-    Node* root = treeScope().rootNode();
+    Node* root = treeScope()->rootNode();
     return root && root->isShadowRoot() ? toShadowRoot(root) : 0;
 }
 
@@ -1707,7 +1707,7 @@ unsigned short Node::compareDocumentPositionInternal(const Node* otherNode, Shad
     // If one node is in the document and the other is not, we must be disconnected.
     // If the nodes have different owning documents, they must be disconnected.  Note that we avoid
     // comparing Attr nodes here, since they return false from inDocument() all the time (which seems like a bug).
-    if (start1->inDocument() != start2->inDocument() || (treatment == TreatShadowTreesAsDisconnected && &start1->treeScope() != &start2->treeScope())) {
+    if (start1->inDocument() != start2->inDocument() || (treatment == TreatShadowTreesAsDisconnected && start1->treeScope() != start2->treeScope())) {
         unsigned short direction = (this > otherNode) ? DOCUMENT_POSITION_PRECEDING : DOCUMENT_POSITION_FOLLOWING;
         return DOCUMENT_POSITION_DISCONNECTED | DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC | direction;
     }
@@ -1728,7 +1728,7 @@ unsigned short Node::compareDocumentPositionInternal(const Node* otherNode, Shad
         return DOCUMENT_POSITION_DISCONNECTED | DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC | direction;
     }
 
-    unsigned connection = &start1->treeScope() != &start2->treeScope() ? DOCUMENT_POSITION_DISCONNECTED | DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC : 0;
+    unsigned connection = start1->treeScope() != start2->treeScope() ? DOCUMENT_POSITION_DISCONNECTED | DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC : 0;
 
     // Walk the two chains backwards and look for the first difference.
     for (unsigned i = min(index1, index2); i; --i) {
@@ -2507,7 +2507,7 @@ void Node::removedLastRef()
     // faster for non-Document nodes, and because the call to removedLastRef that is inlined
     // at all deref call sites is smaller if it's a non-virtual function.
     if (isTreeScope()) {
-        treeScope().removedLastRefToScope();
+        treeScope()->removedLastRefToScope();
         return;
     }