Add support for mapping node tree on the client.

mojo/services/public/cpp/view_manager/lib/view_manager_private.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_PRIVATE_H_
 #define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_LIB_VIEW_MANAGER_PRIVATE_H_
 
 #include "base/basictypes.h"
+#include "mojo/services/public/cpp/view_manager/lib/view_manager_synchronizer.h"
 #include "mojo/services/public/cpp/view_manager/view_manager.h"
 
 namespace mojo {
 namespace services {
 namespace view_manager {
 
+class ViewManagerObserver;
 class ViewManagerSynchronizer;
 
 class ViewManagerPrivate {
  public:
   explicit ViewManagerPrivate(ViewManager* manager);
   ~ViewManagerPrivate();
 
   ViewManagerSynchronizer* synchronizer() {
     return manager_->synchronizer_.get();
   }
   Shell* shell() { return manager_->shell_; }
 
+  void set_tree(ViewTreeNode* root) { manager_->tree_.reset(root); }
+
+  // Returns true if the ViewManager's synchronizer is connected to the service.
+  bool connected() { return manager_->synchronizer_->connected(); }
+
+  void AddObserver(ViewManagerObserver* observer) {
+    manager_->AddObserver(observer);
+  }
+  void RemoveObserver(ViewManagerObserver* observer) {
+    manager_->RemoveObserver(observer);
+  }
+  ObserverList<ViewManagerObserver>* observers() {
+    return &manager_->observers_;
+  }
+
  private:
   ViewManager* manager_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewManagerPrivate);
 };
 
 }  // namespace view_manager
 }  // namespace services
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_LIB_VIEW_MANAGER_PRIVATE_H_