Bug 1067287 - DevTools Timeline: Fix intermittent browser_timeline_overview-initial-selection-02.js failures due to very unlikely race condition. r=vp

--HG--
extra : rebase_source : 17d6eab31b44b0716ffb154a951637f4367deb0d

browser/devtools/timeline/timeline.js

@@ -132,8 +132,8 @@ let TimelineController = {
    * updating the UI as needed.
    */
   _stopRecordingAndDiscardData: function*() {
-    this._markers.length = 0;
     yield this._stopRecording();
+    this._markers.length = 0;
   },
 
   /**