Bug 1001120 - Introduce a test for slow subframe loads invalidating S…

…ession History. r=ttaubert

browser/components/sessionstore/content/content-sessionStore.js

@@ -216,11 +216,9 @@ let SyncHandler = {
  */
 let SessionHistoryListener = {
   init: function () {
-    // The frame tree observer is needed to handle navigating away from
-    // an about page. Currently nsISHistoryListener does not have
-    // OnHistoryNewEntry() called for about pages because the history entry is
-    // modified to point at the new page. Once Bug 981900 lands the frame tree
-    // observer can be removed.
+    // The frame tree observer is needed to handle initial subframe loads.
+    // It will redundantly invalidate with the SHistoryListener in some cases
+    // but these invalidations are very cheap.
     gFrameTree.addObserver(this);
 
     // By adding the SHistoryListener immediately, we will unfortunately be

browser/components/sessionstore/test/browser_sessionHistory_slow.sjs

@@ -0,0 +1,21 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+const DELAY_MS = "2000";
+
+let timer;
+
+function handleRequest(req, resp) {
+  resp.processAsync();
+  resp.setHeader("Cache-Control", "no-cache", false);
+  resp.setHeader("Content-Type", "text/html;charset=utf-8", false);
+
+  timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+  timer.init(() => {
+    resp.write("hi");
+    resp.finish();
+  }, DELAY_MS, Ci.nsITimer.TYPE_ONE_SHOT);
+}