Make sure that Content Handled application can be connected multiple times.

mojo/shell/view_manager_loader.cc

Index: mojo/shell/view_manager_loader.cc
diff --git a/mojo/shell/view_manager_loader.cc b/mojo/shell/view_manager_loader.cc
index 91280846383d8dd34791bd6b6231806db2aa4770..d47f183ec92eb136de70e0d3401cb4e59646e083 100644
--- a/mojo/shell/view_manager_loader.cc
+++ b/mojo/shell/view_manager_loader.cc
@@ -22,7 +22,7 @@ ViewManagerLoader::~ViewManagerLoader() {
 
 void ViewManagerLoader::Load(ApplicationManager* manager,
                              const GURL& url,
-                             scoped_refptr<LoadCallbacks> callbacks) {
+                             LoadCallback callbacks) {
   ScopedMessagePipeHandle shell_handle = callbacks->RegisterApplication();
   if (!shell_handle.is_valid())
     return;