Add support for mapping node tree on the client.

mojo/services/public/cpp/view_manager/lib/view_manager_private.h

Index: mojo/services/public/cpp/view_manager/lib/view_manager_private.h
diff --git a/mojo/services/public/cpp/view_manager/lib/view_manager_private.h b/mojo/services/public/cpp/view_manager/lib/view_manager_private.h
index 071404ba09ce481c01d73efcb352b41885b80d52..50c058fba58f22b10e4321522f55854de1aa1dc7 100644
--- a/mojo/services/public/cpp/view_manager/lib/view_manager_private.h
+++ b/mojo/services/public/cpp/view_manager/lib/view_manager_private.h
@@ -6,12 +6,14 @@
 #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 {
@@ -24,6 +26,21 @@ class ViewManagerPrivate {
   }
   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_;