Add support for multiple roots to the client lib.

mojo/examples/window_manager/window_manager.cc

 // 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 "base/basictypes.h"
+#include "base/bind.h"
 #include "mojo/public/cpp/application/application.h"
 #include "mojo/services/public/cpp/view_manager/view.h"
 #include "mojo/services/public/cpp/view_manager/view_manager.h"
 #include "mojo/services/public/cpp/view_manager/view_tree_node.h"
 
 namespace mojo {
 namespace examples {
 
 class WindowManager : public Application {
  public:
   WindowManager() {}
   virtual ~WindowManager() {}
 
  private:
   // Overridden from Application:
   virtual void Initialize() MOJO_OVERRIDE {
-    view_manager_ = view_manager::ViewManager::CreateBlocking(this);
+    view_manager_ = view_manager::ViewManager::CreateBlocking(this,
+        base::Bind(&WindowManager::OnRootAdded, base::Unretained(this)));
     view_manager::ViewTreeNode* node =
         view_manager::ViewTreeNode::Create(view_manager_);
-    view_manager_->tree()->AddChild(node);
+    view_manager_->roots().front()->AddChild(node);
     node->SetBounds(gfx::Rect(800, 600));
 
     view_manager::View* view = view_manager::View::Create(view_manager_);
     node->SetActiveView(view);
     view->SetColor(SK_ColorBLUE);
 
     view_manager::ViewTreeNode* embedded =
         view_manager::ViewTreeNode::Create(view_manager_);
     node->AddChild(embedded);
     embedded->SetBounds(gfx::Rect(50, 50, 200, 200));
-    view_manager_->Embed("mojo:mojo_embedded_app", embedded);
+    embedded->Embed("mojo:mojo_embedded_app");
+
+    view_manager::ViewTreeNode* embedded2 =
+        view_manager::ViewTreeNode::Create(view_manager_);
+    node->AddChild(embedded2);
+    embedded2->SetBounds(gfx::Rect(250, 250, 200, 200));
+    embedded2->Embed("mojo:mojo_embedded_app");
   }
 
+  void OnRootAdded(view_manager::ViewManager* view_manager) {}
+
   view_manager::ViewManager* view_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManager);
 };
 
 }  // namespace examples
 
 // static
 Application* Application::Create() {
   return new examples::WindowManager;
 }
 
 }  // namespace mojo