Use ShellPtr type in ApplicationLoader instead of untyped handles

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

Index: mojo/public/cpp/application/lib/application_impl.cc
diff --git a/mojo/public/cpp/application/lib/application_impl.cc b/mojo/public/cpp/application/lib/application_impl.cc
index 894060d8bf2eb064a7585c442429622c4320d8da..bea97a110a77eb328e74f00d66be6db34f77dc83 100644
--- a/mojo/public/cpp/application/lib/application_impl.cc
+++ b/mojo/public/cpp/application/lib/application_impl.cc
@@ -24,6 +24,11 @@ class ApplicationImpl::ShellPtrWatcher : public ErrorHandler {
   MOJO_DISALLOW_COPY_AND_ASSIGN(ShellPtrWatcher);
 };
 
+ApplicationImpl::ApplicationImpl(ApplicationDelegate* delegate, ShellPtr shell)
+    : initialized_(false), delegate_(delegate), shell_watch_(nullptr) {
+  BindShell(shell.PassMessagePipe());
+}
+
 ApplicationImpl::ApplicationImpl(ApplicationDelegate* delegate,
                                  ScopedMessagePipeHandle shell_handle)
     : initialized_(false), delegate_(delegate), shell_watch_(nullptr) {