Bug 1626278: Remove transports from main, just like we do under normal circumstances. r=mjf

Differential Revision: https://phabricator.services.mozilla.com/D93262

dom/media/webrtc/jsapi/PeerConnectionMedia.cpp

@@ -628,6 +628,9 @@ void PeerConnectionMedia::SelfDestruct_m() {
 
   ASSERT_ON_THREAD(mMainThread);
 
+  mTransportHandler->RemoveTransportsExcept(std::set<std::string>());
+  mTransportHandler = nullptr;
+
   mMainThread = nullptr;
 
   // Final self-destruct.
@@ -641,9 +644,6 @@ void PeerConnectionMedia::ShutdownMediaTransport_s() {
 
   disconnect_all();
 
-  mTransportHandler->RemoveTransportsExcept(std::set<std::string>());
-  mTransportHandler = nullptr;
-
   // we're holding a ref to 'this' that's released by SelfDestruct_m
   mMainThread->Dispatch(
       WrapRunnable(this, &PeerConnectionMedia::SelfDestruct_m),