Add support for mapping node tree on the client.

mojo/services/public/cpp/view_manager/lib/view_manager.cc

Index: mojo/services/public/cpp/view_manager/lib/view_manager.cc
diff --git a/mojo/services/public/cpp/view_manager/lib/view_manager.cc b/mojo/services/public/cpp/view_manager/lib/view_manager.cc
index 7fd82e7617a8bf39ae332593d50a167b0cb15912..3c45538281b797933354e65c26532d461a0fe9b2 100644
--- a/mojo/services/public/cpp/view_manager/lib/view_manager.cc
+++ b/mojo/services/public/cpp/view_manager/lib/view_manager.cc
@@ -1,20 +1,32 @@
 // 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.
-
-#include "mojo/services/public/cpp/view_manager/view_manager.h"
-
-#include "mojo/services/public/cpp/view_manager/lib/view_manager_synchronizer.h"
-
-namespace mojo {
-namespace services {
-namespace view_manager {
-
-ViewManager::ViewManager(Shell* shell)
-    : shell_(shell),
-      synchronizer_(new ViewManagerSynchronizer(this)) {}
-ViewManager::~ViewManager() {}
-
-}  // namespace view_manager
-}  // namespace services
-}  // namespace mojo
+
+#include "mojo/services/public/cpp/view_manager/view_manager.h"
+
+#include "mojo/services/public/cpp/view_manager/lib/view_manager_synchronizer.h"
+
+namespace mojo {
+namespace services {
+namespace view_manager {
+
+ViewManager::ViewManager(Shell* shell)
+    : shell_(shell),
+      synchronizer_(new ViewManagerSynchronizer(this)) {}
+ViewManager::~ViewManager() {}
+
+void ViewManager::BuildNodeTree(const mojo::Callback<void()>& callback) {
+  synchronizer_->BuildNodeTree(callback);
+}
+
+void ViewManager::AddObserver(ViewManagerObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void ViewManager::RemoveObserver(ViewManagerObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+}  // namespace view_manager
+}  // namespace services
+}  // namespace mojo