Tweaks to ViewManager:

mojo/services/view_manager/node.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SERVICES_VIEW_MANAGER_NODE_H_
 #define MOJO_SERVICES_VIEW_MANAGER_NODE_H_
 
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 21 matching lines @@
   void set_view_id(const ViewId& view_id) { view_id_ = view_id; }
   const ViewId& view_id() const { return view_id_; }
 
   const NodeId& id() const { return id_; }
 
   void Add(Node* child);
   void Remove(Node* child);
 
   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:
   virtual void OnWindowHierarchyChanged(
       const aura::WindowObserver::HierarchyChangeParams& params) OVERRIDE;
 
   // WindowDelegate overrides:
   virtual gfx::Size GetMinimumSize() const OVERRIDE;
   virtual gfx::Size GetMaximumSize() const OVERRIDE;
   virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
@@ skipping 24 matching lines @@
   aura::Window window_;
 
   DISALLOW_COPY_AND_ASSIGN(Node);
 };
 
 }  // namespace service
 }  // namespace view_manager
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_VIEW_MANAGER_NODE_H_