Add support for multiple roots to the client lib.

mojo/examples/window_manager/window_manager.cc

Index: mojo/examples/window_manager/window_manager.cc
diff --git a/mojo/examples/window_manager/window_manager.cc b/mojo/examples/window_manager/window_manager.cc
index e3e88ac08e698b4fa0f8f09e54d768dbac934c47..e43fa0896a565fcc189b2b389f3029fd40bb16d2 100644
--- a/mojo/examples/window_manager/window_manager.cc
+++ b/mojo/examples/window_manager/window_manager.cc
@@ -3,6 +3,7 @@
 // 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"
@@ -19,10 +20,11 @@ class WindowManager : public Application {
  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_);
@@ -33,9 +35,17 @@ class WindowManager : public Application {
         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);