Bug 1147857: followup patch to continue BuildStats cleanup r=jib

media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp

@@ -2810,13 +2810,6 @@ PeerConnectionImpl::BuildStatsQuery_m(
     return NS_ERROR_UNEXPECTED;
   }
 
-  // Note: mMedia->ice_ctx() is deleted on STS thread; so make sure we grab and hold
-  // a ref instead of making multiple calls.  NrIceCtx uses threadsafe refcounting.
-  query->iceCtx = mMedia->ice_ctx();
-  if (!query->iceCtx) {
-    CSFLogError(logTag, "Could not build stats query, no ice_ctx");
-    return NS_ERROR_UNEXPECTED;
-  }
   if (!mThread) {
     CSFLogError(logTag, "Could not build stats query, no MainThread");
     return NS_ERROR_UNEXPECTED;
@@ -2828,6 +2821,16 @@ PeerConnectionImpl::BuildStatsQuery_m(
     return rv;
   }
 
+  // Note: mMedia->ice_ctx() is deleted on STS thread; so make sure we grab and hold
+  // a ref instead of making multiple calls.  NrIceCtx uses threadsafe refcounting.
+  // NOTE: Do this after all other failure tests, to ensure we don't
+  // accidentally release the Ctx on Mainthread.
+  query->iceCtx = mMedia->ice_ctx();
+  if (!query->iceCtx) {
+    CSFLogError(logTag, "Could not build stats query, no ice_ctx");
+    return NS_ERROR_UNEXPECTED;
+  }
+
   // We do not use the pcHandle here, since that's risky to expose to content.
   query->report = new RTCStatsReportInternalConstruct(
       NS_ConvertASCIItoUTF16(mName.c_str()),

media/webrtc/signaling/src/peerconnection/WebrtcGlobalInformation.cpp

@@ -167,13 +167,18 @@ WebrtcGlobalInformation::GetAllStats(
           pcIdFilter.Value().EqualsASCII(p->second->GetIdAsAscii().c_str())) {
         if (p->second->HasMedia()) {
           queries->append(nsAutoPtr<RTCStatsQuery>(new RTCStatsQuery(true)));
-          p->second->BuildStatsQuery_m(nullptr, // all tracks
-                                       queries->back());
+          if (NS_WARN_IF(NS_FAILED(p->second->BuildStatsQuery_m(nullptr, // all tracks
+                                                                queries->back())))) {
+            queries->popBack();
+          } else {
+            MOZ_ASSERT(queries->back()->report);
+          }
         }
       }
     }
   }
 
+  if (!queries->empty()) {
     // CallbackObject does not support threadsafe refcounting, and must be
     // destroyed on main.
     nsMainThreadPtrHandle<WebrtcGlobalStatisticsCallback> callbackHandle(
@@ -184,6 +189,9 @@ WebrtcGlobalInformation::GetAllStats(
                        NS_DISPATCH_NORMAL);
 
     aRv = rv;
+  } else {
+    aRv = NS_OK;
+  }
 }
 
 void