Bug 1258361 - Wait for second streaming response to display. r=vporof

MozReview-Commit-ID: LV9O4BOThw0

devtools/client/netmonitor/test/browser_net_streaming-response.js

@@ -48,6 +48,7 @@ function test() {
 
     RequestsMenu.selectedIndex = 1;
     yield panelWin.once(panelWin.EVENTS.TAB_UPDATED);
+    yield panelWin.once(panelWin.EVENTS.RESPONSE_BODY_DISPLAYED);
 
     testEditorContent(editor, REQUESTS[1]); // the mpeg-dash part