Bug 1634846 - P1. Remove unused method. r=nika,jld

And the less use of MessageLoop, the better.

Differential Revision: https://phabricator.services.mozilla.com/D80654

ipc/glue/ProtocolUtils.cpp

@@ -589,14 +589,6 @@ bool IToplevelProtocol::Open(UniquePtr<Transport> aTransport,
   return GetIPCChannel()->Open(std::move(aTransport), aThread, aSide);
 }
 
-bool IToplevelProtocol::Open(MessageChannel* aChannel,
-                             MessageLoop* aMessageLoop,
-                             mozilla::ipc::Side aSide) {
-  SetOtherProcessId(base::GetCurrentProcId());
-  return GetIPCChannel()->Open(aChannel, aMessageLoop->SerialEventTarget(),
-                               aSide);
-}
-
 bool IToplevelProtocol::Open(MessageChannel* aChannel,
                              nsISerialEventTarget* aEventTarget,
                              mozilla::ipc::Side aSide) {

ipc/glue/ProtocolUtils.h

@@ -430,9 +430,6 @@ class IToplevelProtocol : public IProtocol {
             MessageLoop* aThread = nullptr,
             mozilla::ipc::Side aSide = mozilla::ipc::UnknownSide);
 
-  bool Open(MessageChannel* aChannel, MessageLoop* aMessageLoop,
-            mozilla::ipc::Side aSide = mozilla::ipc::UnknownSide);
-
   bool Open(MessageChannel* aChannel, nsISerialEventTarget* aEventTarget,
             mozilla::ipc::Side aSide = mozilla::ipc::UnknownSide);