Mojo C++ bindings: remove unnecessary getters/params of AssociatedGroup.

mojo/public/cpp/bindings/tests/bind_task_runner_unittest.cc

Index: mojo/public/cpp/bindings/tests/bind_task_runner_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/bind_task_runner_unittest.cc b/mojo/public/cpp/bindings/tests/bind_task_runner_unittest.cc
index 7a1512baa729efc5f8bb185fed08e3774078f2e5..0c777ec410e8eccebb6f04a58a9f699177de26b4 100644
--- a/mojo/public/cpp/bindings/tests/bind_task_runner_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/bind_task_runner_unittest.cc
@@ -222,7 +222,7 @@ class AssociatedBindTaskRunnerTest : public testing::Test {
                    base::Unretained(this)));
 
     connection_ptr_->GetSender(
-        MakeRequest(&sender_ptr_, nullptr, sender_ptr_task_runner_));
+        MakeRequest(&sender_ptr_, sender_ptr_task_runner_));
     connection_binding_task_runner_->Run();
   }