diff --git a/ipc/glue/MessageChannel.cpp b/ipc/glue/MessageChannel.cpp
index 8e3776b8a4c9..b684bd342c01 100644
--- a/ipc/glue/MessageChannel.cpp
+++ b/ipc/glue/MessageChannel.cpp
@@ -1859,13 +1859,13 @@ MessageChannel::MaybeUndeferIncall()
 void
 MessageChannel::EnteredCxxStack()
 {
-    mListener->OnEnteredCxxStack();
+    mListener->EnteredCxxStack();
 }
 
 void
 MessageChannel::ExitedCxxStack()
 {
-    mListener->OnExitedCxxStack();
+    mListener->ExitedCxxStack();
     if (mSawInterruptOutMsg) {
         MonitorAutoLock lock(*mMonitor);
         // see long comment in OnMaybeDequeueOne()
@@ -1877,13 +1877,13 @@ MessageChannel::ExitedCxxStack()
 void
 MessageChannel::EnteredCall()
 {
-    mListener->OnEnteredCall();
+    mListener->EnteredCall();
 }
 
 void
 MessageChannel::ExitedCall()
 {
-    mListener->OnExitedCall();
+    mListener->ExitedCall();
 }
 
 void
@@ -1983,7 +1983,7 @@ MessageChannel::ShouldContinueFromTimeout()
     bool cont;
     {
         MonitorAutoUnlock unlock(*mMonitor);
-        cont = mListener->OnReplyTimeout();
+        cont = mListener->ShouldContinueFromReplyTimeout();
         mListener->ArtificialSleep();
     }
 
@@ -2032,7 +2032,7 @@ void
 MessageChannel::ReportMessageRouteError(const char* channelName) const
 {
     PrintErrorMessage(mSide, channelName, "Need a route");
-    mListener->OnProcessingError(MsgRouteError, "MsgRouteError");
+    mListener->ProcessingError(MsgRouteError, "MsgRouteError");
 }
 
 void
@@ -2074,7 +2074,7 @@ MessageChannel::ReportConnectionError(const char* aChannelName, Message* aMsg) c
     }
 
     MonitorAutoUnlock unlock(*mMonitor);
-    mListener->OnProcessingError(MsgDropped, errorMsg);
+    mListener->ProcessingError(MsgDropped, errorMsg);
 }
 
 bool
@@ -2119,7 +2119,7 @@ MessageChannel::MaybeHandleError(Result code, const Message& aMsg, const char* c
 
     PrintErrorMessage(mSide, channelName, reason);
 
-    mListener->OnProcessingError(code, reason);
+    mListener->ProcessingError(code, reason);
 
     return false;
 }
diff --git a/ipc/glue/ProtocolUtils.cpp b/ipc/glue/ProtocolUtils.cpp
index 3857b6dc06b8..b096bf68ae36 100644
--- a/ipc/glue/ProtocolUtils.cpp
+++ b/ipc/glue/ProtocolUtils.cpp
@@ -521,5 +521,11 @@ IProtocol::DeallocShmem(Shmem& aMem)
   return ok;
 }
 
+bool
+IToplevelProtocol::IsOnCxxStack() const
+{
+  return GetIPCChannel()->IsOnCxxStack();
+}
+
 } // namespace ipc
 } // namespace mozilla
diff --git a/ipc/glue/ProtocolUtils.h b/ipc/glue/ProtocolUtils.h
index ea926b2a9e78..31ab03ef4cd8 100644
--- a/ipc/glue/ProtocolUtils.h
+++ b/ipc/glue/ProtocolUtils.h
@@ -65,6 +65,8 @@ class NeckoParent;
 
 namespace ipc {
 
+class MessageChannel;
+
 #ifdef XP_WIN
 const base::ProcessHandle kInvalidProcessHandle = INVALID_HANDLE_VALUE;
 
@@ -231,9 +233,10 @@ public:
 
     virtual void OnChannelClose() = 0;
     virtual void OnChannelError() = 0;
-    virtual void OnProcessingError(Result aError, const char* aMsgName) = 0;
+    virtual void ProcessingError(Result aError, const char* aMsgName) {}
     virtual void OnChannelConnected(int32_t peer_pid) {}
-    virtual bool OnReplyTimeout() {
+
+    virtual bool ShouldContinueFromReplyTimeout() {
         return false;
     }
 
@@ -269,18 +272,13 @@ public:
     void ArtificialSleep() {}
 #endif
 
-    virtual void OnEnteredCxxStack() {
-        NS_RUNTIMEABORT("default impl shouldn't be invoked");
-    }
-    virtual void OnExitedCxxStack() {
-        NS_RUNTIMEABORT("default impl shouldn't be invoked");
-    }
-    virtual void OnEnteredCall() {
-        NS_RUNTIMEABORT("default impl shouldn't be invoked");
-    }
-    virtual void OnExitedCall() {
-        NS_RUNTIMEABORT("default impl shouldn't be invoked");
-    }
+    virtual void EnteredCxxStack() {}
+    virtual void ExitedCxxStack() {}
+    virtual void EnteredCall() {}
+    virtual void ExitedCall() {}
+
+    bool IsOnCxxStack() const;
+
     virtual RacyInterruptPolicy MediateInterruptRace(const MessageInfo& parent,
                                                      const MessageInfo& child)
     {
diff --git a/ipc/ipdl/ipdl/lower.py b/ipc/ipdl/ipdl/lower.py
index 45602d389559..eb3e25bed31a 100644
--- a/ipc/ipdl/ipdl/lower.py
+++ b/ipc/ipdl/ipdl/lower.py
@@ -3221,61 +3221,12 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
         deallocshmemvar = ExprVar('DeallocShmems')
         deallocselfvar = ExprVar('Dealloc' + _actorName(ptype.name(), self.side))
 
-        if ptype.isToplevel():
-            # OnProcesingError(code)
-            codevar = ExprVar('aCode')
-            reasonvar = ExprVar('aReason')
-            onprocessingerror = MethodDefn(
-                MethodDecl('OnProcessingError',
-                           params=[ Param(_Result.Type(), codevar.name),
-                                    Param(Type('char', const=1, ptr=1), reasonvar.name) ]))
-            onprocessingerror.addstmt(StmtReturn(
-                ExprCall(p.processingErrorVar(), args=[ codevar, reasonvar ])))
-            self.cls.addstmts([ onprocessingerror, Whitespace.NL ])
-
         # int32_t GetProtocolTypeId() { return PFoo; }
         gettypetag = MethodDefn(
             MethodDecl('GetProtocolTypeId', ret=_actorTypeTagType()))
         gettypetag.addstmt(StmtReturn(_protocolId(ptype)))
         self.cls.addstmts([ gettypetag, Whitespace.NL ])
 
-        if ptype.isToplevel():
-            # OnReplyTimeout()
-            if toplevel.isSync() or toplevel.isInterrupt():
-                ontimeout = MethodDefn(
-                    MethodDecl('OnReplyTimeout', ret=Type.BOOL))
-                ontimeout.addstmt(StmtReturn(
-                    ExprCall(p.shouldContinueFromTimeoutVar())))
-                self.cls.addstmts([ ontimeout, Whitespace.NL ])
-
-        # C++-stack-related methods
-        if ptype.isToplevel():
-            # OnEnteredCxxStack()
-            onentered = MethodDefn(MethodDecl('OnEnteredCxxStack'))
-            onentered.addstmt(StmtReturn(ExprCall(p.enteredCxxStackVar())))
-
-            # OnExitedCxxStack()
-            onexited = MethodDefn(MethodDecl('OnExitedCxxStack'))
-            onexited.addstmt(StmtReturn(ExprCall(p.exitedCxxStackVar())))
-
-            # OnEnteredCxxStack()
-            onenteredcall = MethodDefn(MethodDecl('OnEnteredCall'))
-            onenteredcall.addstmt(StmtReturn(ExprCall(p.enteredCallVar())))
-
-            # OnExitedCxxStack()
-            onexitedcall = MethodDefn(MethodDecl('OnExitedCall'))
-            onexitedcall.addstmt(StmtReturn(ExprCall(p.exitedCallVar())))
-
-            # bool IsOnCxxStack()
-            onstack = MethodDefn(
-                MethodDecl(p.onCxxStackVar().name, ret=Type.BOOL, const=1))
-            onstack.addstmt(StmtReturn(ExprCall(
-                ExprSelect(p.channelVar(), '.', p.onCxxStackVar().name))))
-
-            self.cls.addstmts([ onentered, onexited,
-                                onenteredcall, onexitedcall,
-                                onstack, Whitespace.NL ])
-
         if ptype.isToplevel():
             # OnChannelClose()
             onclose = MethodDefn(MethodDecl('OnChannelClose'))