Launch nexes from mojo_shell.

mojo/nacl/monacl_shell.cc

Index: mojo/nacl/monacl_shell.cc
diff --git a/mojo/nacl/monacl_shell.cc b/mojo/nacl/monacl_shell.cc
index 7922d9a60de241470762cd22cf15ba103a477bb4..0efe2a705d8972f2c99a42dbd43fcbf399da3175 100644
--- a/mojo/nacl/monacl_shell.cc
+++ b/mojo/nacl/monacl_shell.cc
@@ -23,6 +23,7 @@ int main(int argc, char* argv[]) {
       new mojo::embedder::SimplePlatformSupport()));
 
   // Does not return.
-  mojo::LaunchNaCl(nexe_file, irt_file, argc - 2, argv + 2);
+  mojo::LaunchNaCl(nexe_file, irt_file, argc - 2, argv + 2,
+                   MOJO_HANDLE_INVALID);
   return 1;
 }