Bug 1231975 - Part 3: Break a reference cycle between PendingResolution and DNSRequestChild. r=drno

MozReview-Commit-ID: CS1q6LyUsIe

--HG--
extra : rebase_source : efc3eb166d01de91c2d628540fda625155d8cd26

media/mtransport/nriceresolver.cpp

@@ -199,7 +199,7 @@ nsresult NrIceResolver::PendingResolution::OnLookupComplete(
   ASSERT_ON_THREAD(thread_);
   // First check if we've been canceled. This is single-threaded on the STS
   // thread, but cancel() cannot guarantee this event isn't on the queue.
-  if (!canceled_) {
+  if (request_) {
     nr_transport_addr *cb_addr = nullptr;
     nr_transport_addr ta;
     // TODO(jib@mozilla.com): Revisit when we do TURN.
@@ -212,6 +212,7 @@ nsresult NrIceResolver::PendingResolution::OnLookupComplete(
       }
     }
     cb_(cb_arg_, cb_addr);
+    request_ = nullptr;
     Release();
   }
   return NS_OK;
@@ -226,7 +227,7 @@ int NrIceResolver::cancel(void *obj, void *handle) {
 
 int NrIceResolver::PendingResolution::cancel() {
   request_->Cancel (NS_ERROR_ABORT);
-  canceled_ = true; // in case OnLookupComplete is already on event queue.
+  request_ = nullptr;
   Release();
   return 0;
 }

media/mtransport/nriceresolver.h

@@ -95,8 +95,7 @@ class NrIceResolver
         thread_(thread),
         port_(port),
         transport_(transport),
-        cb_(cb), cb_arg_(cb_arg),
-        canceled_ (false) {}
+        cb_(cb), cb_arg_(cb_arg) {}
     NS_IMETHOD OnLookupComplete(nsICancelable *request, nsIDNSRecord *record,
                                 nsresult status) override;
     int cancel();
@@ -110,7 +109,6 @@ class NrIceResolver
     int transport_;
     int (*cb_)(void *cb_arg, nr_transport_addr *addr);
     void *cb_arg_;
-    bool canceled_;
   };
 
   nr_resolver_vtbl* vtbl_;