Make BaseView et al. take an ApplicationConnector instead of an ApplicationImpl.

mojo/public/cpp/application/lib/connect.cc

Index: mojo/public/cpp/application/lib/connect.cc
diff --git a/mojo/public/cpp/application/lib/connect.cc b/mojo/public/cpp/application/lib/connect.cc
index 33130da85a8b3799e9f62cd7544de3d5a4cb45a7..f6957c3c253cb58c3b9ea9d6c75ef96efc6ed331 100644
--- a/mojo/public/cpp/application/lib/connect.cc
+++ b/mojo/public/cpp/application/lib/connect.cc
@@ -14,4 +14,11 @@ InterfaceHandle<ApplicationConnector> CreateApplicationConnector(Shell* shell) {
   return application_connector;
 }
 
+InterfaceHandle<ApplicationConnector> DuplicateApplicationConnector(
+    ApplicationConnector* application_connector) {
+  InterfaceHandle<ApplicationConnector> new_application_connector;
+  application_connector->Duplicate(GetProxy(&new_application_connector));
+  return new_application_connector;
+}
+
 }  // namespace mojo