diff -r 000000000000 -r 6474c204b198 browser/components/sessionstore/test/browser_607016.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/sessionstore/test/browser_607016.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,117 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+let stateBackup = ss.getBrowserState();
+
+function cleanup() {
+  // Reset the pref
+  try {
+    Services.prefs.clearUserPref("browser.sessionstore.restore_on_demand");
+  } catch (e) {}
+  ss.setBrowserState(stateBackup);
+  executeSoon(finish);
+}
+
+function test() {
+  /** Bug 607016 - If a tab is never restored, attributes (eg. hidden) aren't updated correctly **/
+  waitForExplicitFinish();
+  ignoreAllUncaughtExceptions();
+
+  // Set the pref to true so we know exactly how many tabs should be restoring at
+  // any given time. This guarantees that a finishing load won't start another.
+  Services.prefs.setBoolPref("browser.sessionstore.restore_on_demand", true);
+
+  // We have our own progress listener for this test, which we'll attach before our state is set
+  let progressListener = {
+    onStateChange: function (aBrowser, aWebProgress, aRequest, aStateFlags, aStatus) {
+      if (aBrowser.__SS_restoreState == TAB_STATE_RESTORING &&
+          aStateFlags & Ci.nsIWebProgressListener.STATE_STOP &&
+          aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK &&
+          aStateFlags & Ci.nsIWebProgressListener.STATE_IS_WINDOW)
+        progressCallback(aBrowser);
+    }
+  }
+
+  let state = { windows: [{ tabs: [
+    { entries: [{ url: "http://example.org#1" }], extData: { "uniq": r() } },
+    { entries: [{ url: "http://example.org#2" }], extData: { "uniq": r() } }, // overwriting
+    { entries: [{ url: "http://example.org#3" }], extData: { "uniq": r() } }, // hiding
+    { entries: [{ url: "http://example.org#4" }], extData: { "uniq": r() } }, // adding
+    { entries: [{ url: "http://example.org#5" }], extData: { "uniq": r() } }, // deleting
+    { entries: [{ url: "http://example.org#6" }] } // creating
+  ], selected: 1 }] };
+
+  function progressCallback(aBrowser) {
+    // We'll remove the progress listener after the first one because we aren't
+    // loading any other tabs
+    window.gBrowser.removeTabsProgressListener(progressListener);
+
+    let curState = JSON.parse(ss.getBrowserState());
+    for (let i = 0; i < curState.windows[0].tabs.length; i++) {
+      let tabState = state.windows[0].tabs[i];
+      let tabCurState = curState.windows[0].tabs[i];
+      if (tabState.extData) {
+        is(tabCurState.extData["uniq"], tabState.extData["uniq"],
+           "sanity check that tab has correct extData");
+      }
+      else {
+        // We aren't expecting there to be any data on extData, but panorama
+        // may be setting something, so we need to make sure that if we do have
+        // data, we just don't have anything for "uniq".
+        ok(!("extData" in tabCurState) || !("uniq" in tabCurState.extData),
+           "sanity check that tab doesn't have extData or extData doesn't have 'uniq'");
+      }
+    }
+
+    // Now we'll set a new unique value on 1 of the tabs
+    let newUniq = r();
+    ss.setTabValue(gBrowser.tabs[1], "uniq", newUniq);
+    gBrowser.removeTab(gBrowser.tabs[1]);
+    let closedTabData = (JSON.parse(ss.getClosedTabData(window)))[0];
+    is(closedTabData.state.extData.uniq, newUniq,
+       "(overwriting) new data is stored in extData");
+
+    // hide the next tab before closing it
+    gBrowser.hideTab(gBrowser.tabs[1]);
+    gBrowser.removeTab(gBrowser.tabs[1]);
+    closedTabData = (JSON.parse(ss.getClosedTabData(window)))[0];
+    ok(closedTabData.state.hidden, "(hiding) tab data has hidden == true");
+
+    // set data that's not in a conflicting key
+    let stillUniq = r();
+    ss.setTabValue(gBrowser.tabs[1], "stillUniq", stillUniq);
+    gBrowser.removeTab(gBrowser.tabs[1]);
+    closedTabData = (JSON.parse(ss.getClosedTabData(window)))[0];
+    is(closedTabData.state.extData.stillUniq, stillUniq,
+       "(adding) new data is stored in extData");
+
+    // remove the uniq value and make sure it's not there in the closed data
+    ss.deleteTabValue(gBrowser.tabs[1], "uniq");
+    gBrowser.removeTab(gBrowser.tabs[1]);
+    closedTabData = (JSON.parse(ss.getClosedTabData(window)))[0];
+    // Since Panorama might have put data in, first check if there is extData.
+    // If there is explicitly check that "uniq" isn't in it. Otherwise, we're ok
+    if ("extData" in closedTabData.state) {
+      ok(!("uniq" in closedTabData.state.extData),
+         "(deleting) uniq not in existing extData");
+    }
+    else {
+      ok(true, "(deleting) no data is stored in extData");
+    }
+
+    // set unique data on the tab that never had any set, make sure that's saved
+    let newUniq2 = r();
+    ss.setTabValue(gBrowser.tabs[1], "uniq", newUniq2);
+    gBrowser.removeTab(gBrowser.tabs[1]);
+    closedTabData = (JSON.parse(ss.getClosedTabData(window)))[0];
+    is(closedTabData.state.extData.uniq, newUniq2,
+       "(creating) new data is stored in extData where there was none");
+
+    cleanup();
+  }
+
+  window.gBrowser.addTabsProgressListener(progressListener);
+  ss.setBrowserState(JSON.stringify(state));
+}
+