Map new subtrees when they are attached to the node hierarchy visible to a connection.

mojo/services/public/cpp/view_manager/lib/view_manager_synchronizer.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_PUBLIC_CPP_VIEW_MANAGER_LIB_VIEW_MANAGER_SYNCHRONIZER_H_
 #define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_LIB_VIEW_MANAGER_SYNCHRONIZER_H_
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "mojo/services/public/cpp/view_manager/view_manager_types.h"
 #include "mojo/services/public/interfaces/view_manager/view_manager.mojom.h"
 
 namespace base {
 class RunLoop;
 }
 
 namespace mojo {
@@ skipping 22 matching lines @@
   // the connection id high word can be zero. In all cases, the TransportId 0x1
   // refers to the root node.
   void AddChild(TransportNodeId child_id, TransportNodeId parent_id);
   void RemoveChild(TransportNodeId child_id, TransportNodeId parent_id);
 
   bool OwnsNode(TransportNodeId id) const;
   bool OwnsView(TransportViewId id) const;
 
   void SetActiveView(TransportNodeId node_id, TransportViewId view_id);
 
+  void set_changes_acked_callback(const base::Callback<void(void)>& callback) {
+    changes_acked_callback_ = callback;
+  }
+  void ClearChangesAckedCallback() {
+    changes_acked_callback_ = base::Callback<void(void)>();
+  }
+
  private:
   friend class ViewManagerTransaction;
   typedef ScopedVector<ViewManagerTransaction> Transactions;
 
   // Overridden from IViewManagerClient:
   virtual void OnConnectionEstablished(
       TransportConnectionId connection_id,
       TransportChangeId next_server_change_id,
       const mojo::Array<INode>& nodes) OVERRIDE;
   virtual void OnServerChangeIdAdvanced(
@@ skipping 26 matching lines @@
   TransportChangeId next_server_change_id_;
 
   Transactions pending_transactions_;
 
   base::WeakPtrFactory<ViewManagerSynchronizer> sync_factory_;
 
   // Non-NULL while blocking on the connection to |service_| during
   // construction.
   base::RunLoop* init_loop_;
 
+  base::Callback<void(void)> changes_acked_callback_;
+
   IViewManagerPtr service_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewManagerSynchronizer);
 };
 
 }  // namespace view_manager
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_LIB_VIEW_MANAGER_SYNCHRONIZER_H_