Tweaks to ViewManager:

mojo/services/view_manager/node.h

Index: mojo/services/view_manager/node.h
diff --git a/mojo/services/view_manager/node.h b/mojo/services/view_manager/node.h
index 9dda56499a99977d45ffec3085943dc4ecea7f86..b989b049e557c4256c49c5b727265384be3cb821 100644
--- a/mojo/services/view_manager/node.h
+++ b/mojo/services/view_manager/node.h
@@ -39,13 +39,24 @@ class MOJO_VIEW_MANAGER_EXPORT Node
 
   aura::Window* window() { return &window_; }
 
-  Node* GetParent();
+  const Node* GetParent() const;
+  Node* GetParent() {
+    return const_cast<Node*>(const_cast<const Node*>(this)->GetParent());
+  }
+
+  const Node* GetRoot() const;
+  Node* GetRoot() {
+    return const_cast<Node*>(const_cast<const Node*>(this)->GetRoot());
+  }
 
   std::vector<Node*> GetChildren();
 
+  bool Contains(const Node* node) const;
+
   // Sets the view associated with this node. Node does not own its View.
   void SetView(View* view);
   View* view() { return view_; }
+  const View* view() const { return view_; }
 
  private:
   // WindowObserver overrides: