Bug 1213517 - Make applyConstraints() and getSettings() do nothing after stop and shutdown. r=jesup

MozReview-Commit-ID: Ez2Wmsoy617

--HG--
extra : rebase_source : b4efaab09652ce3cc5a421c47574c42c6c22f073

dom/media/MediaManager.cpp

@@ -1132,11 +1132,11 @@ public:
         ApplyConstraints(nsPIDOMWindowInner* aWindow,
                          const MediaTrackConstraints& aConstraints) override
         {
-          if (sInShutdown) {
+          if (sInShutdown || !mListener) {
+            // Track has been stopped, or we are in shutdown. In either case
+            // there's no observable outcome, so pretend we succeeded.
             RefPtr<PledgeVoid> p = new PledgeVoid();
-            p->Reject(new MediaStreamError(aWindow,
-                                           NS_LITERAL_STRING("AbortError"),
-                                           NS_LITERAL_STRING("In shutdown")));
+            p->Resolve(false);
             return p.forget();
           }
           return mListener->ApplyConstraintsToTrack(aWindow, mTrackID, aConstraints);
@@ -1145,7 +1145,9 @@ public:
         void
         GetSettings(dom::MediaTrackSettings& aOutSettings) override
         {
-          mListener->GetSettings(aOutSettings);
+          if (mListener) {
+            mListener->GetSettings(aOutSettings);
+          }
         }
 
         void Stop() override