Bug 1285173 - Netmonitor perf stats: whenDataAvailable should wait for a nonempty request list r=Honza

MozReview-Commit-ID: F4yi7vUdXsM

--HG--
extra : rebase_source : c1f6ff9497a3e0231ab584cb809c0576b8056798

devtools/client/netmonitor/netmonitor-view.js

@@ -1201,7 +1201,7 @@ function whenDataAvailable(dataStore, mandatoryFields) {
   let deferred = promise.defer();
 
   let interval = setInterval(() => {
-    if (dataStore.every(item => {
+    if (dataStore.length > 0 && dataStore.every(item => {
       return mandatoryFields.every(field => field in item);
     })) {
       clearInterval(interval);