Makes it so a node can only the root of one connection at a time

mojo/services/view_manager/view_manager_service_impl.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_VIEW_MANAGER_SERVICE_IMPL_H_
 #define MOJO_SERVICES_VIEW_MANAGER_VIEW_MANAGER_SERVICE_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 50 matching lines @@
   }
   const Node* GetNode(const NodeId& id) const;
 
   // Returns the View with the specified id.
   View* GetView(const ViewId& id) {
     return const_cast<View*>(
         const_cast<const ViewManagerServiceImpl*>(this)->GetView(id));
   }
   const View* GetView(const ViewId& id) const;
 
+  // Returns true if this has |id| as a root.
+  bool HasRoot(const NodeId& id) const;
+
   // Invoked when a connection is destroyed.
   void OnViewManagerServiceImplDestroyed(ConnectionSpecificId id);
 
   // The following methods are invoked after the corresponding change has been
   // processed. They do the appropriate bookkeeping and update the client as
   // necessary.
   void ProcessNodeBoundsChanged(const Node* node,
                                 const gfx::Rect& old_bounds,
                                 const gfx::Rect& new_bounds,
                                 bool originated_change);
@@ skipping 53 matching lines @@
   bool DeleteViewImpl(ViewManagerServiceImpl* source, const ViewId& view_id);
 
   // Sets the view associated with a node.
   bool SetViewImpl(Node* node, const ViewId& view_id);
 
   // If |node| is known (in |known_nodes_|) does nothing. Otherwise adds |node|
   // to |nodes|, marks |node| as known and recurses.
   void GetUnknownNodesFrom(const Node* node, std::vector<const Node*>* nodes);
 
   // Removes |node| and all its descendants from |known_nodes_|. This does not
-  // recurse through nodes that were created by this connection.
-  void RemoveFromKnown(const Node* node);
+  // recurse through nodes that were created by this connection. All nodes owned
+  // by this connection are added to |local_nodes|.
+  void RemoveFromKnown(const Node* node, std::vector<Node*>* local_nodes);
 
-  // Adds |transport_node_id| to the set of roots this connection knows about.
-  // Returns true if |transport_node_id| was not already a root for this
-  // connection.
-  bool AddRoot(Id transport_node_id);
+  // Adds |node_id| to the set of roots this connection knows about. The caller
+  // should have verified |node_id| is not among the roots of this connection.
+  void AddRoot(const NodeId& node_id);
+
+  // Removes |node_id| from the set of roots this connection knows about.
+  void RemoveRoot(const NodeId& node_id);
 
   // Returns true if |node| is a non-null and a descendant of |roots_| (or
   // |roots_| is empty).
   bool IsNodeDescendantOfRoots(const Node* node) const;
 
   // Returns true if notification should be sent of a hierarchy change. If true
   // is returned, any nodes that need to be sent to the client are added to
   // |to_send|.
   bool ShouldNotifyOnHierarchyChange(const Node* node,
                                      const Node** new_parent,
@@ skipping 94 matching lines @@
 
 #if defined(OS_WIN)
 #pragma warning(pop)
 #endif
 
 }  // namespace service
 }  // namespace view_manager
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_VIEW_MANAGER_VIEW_MANAGER_SERVICE_IMPL_H_