Rationalize AddAwakable...() and RemoveAwakable...() methods.

mojo/edk/system/message_pipe_test_utils.cc

Index: mojo/edk/system/message_pipe_test_utils.cc
diff --git a/mojo/edk/system/message_pipe_test_utils.cc b/mojo/edk/system/message_pipe_test_utils.cc
index 25c6dfe25e1ca0327a70418cd0821b26c2c8a4fc..5ecef0b40f3cf6449bada7d32b848ccccb8c8085 100644
--- a/mojo/edk/system/message_pipe_test_utils.cc
+++ b/mojo/edk/system/message_pipe_test_utils.cc
@@ -30,7 +30,7 @@ MojoResult WaitIfNecessary(MessagePipe* mp,
   waiter.Init();
 
   MojoResult add_result =
-      mp->AddAwakable(0, &waiter, signals, false, 0, signals_state);
+      mp->AddAwakable(0, &waiter, 0, false, signals, signals_state);
   if (add_result != MOJO_RESULT_OK) {
     return (add_result == MOJO_RESULT_ALREADY_EXISTS) ? MOJO_RESULT_OK
                                                       : add_result;
@@ -38,7 +38,7 @@ MojoResult WaitIfNecessary(MessagePipe* mp,
 
   MojoResult wait_result =
       waiter.Wait(MOJO_DEADLINE_INDEFINITE, nullptr, nullptr);
-  mp->RemoveAwakable(0, &waiter, signals_state);
+  mp->RemoveAwakable(0, false, &waiter, 0, signals_state);
   return wait_result;
 }