Bug 702556 - JS exception "aTabs[0].linkedBrowser is null" in nsSessionStore.js [r=dietrich]

browser/components/sessionstore/src/nsSessionStore.js

@@ -2981,8 +2981,9 @@ SessionStoreService.prototype = {
   restoreHistory:
     function sss_restoreHistory(aWindow, aTabs, aTabData, aIdMap, aDocIdentMap) {
     var _this = this;
-    while (aTabs.length > 0 && (!aTabs[0].linkedBrowser.__SS_tabStillLoading || !aTabs[0].parentNode)) {
-      aTabs.shift(); // this tab got removed before being completely restored
+    // if the tab got removed before being completely restored, then skip it
+    while (aTabs.length > 0 && !(this._canRestoreTabHistory(aTabs[0]))) {
+      aTabs.shift();
       aTabData.shift();
     }
     if (aTabs.length == 0) {
@@ -3996,6 +3997,20 @@ SessionStoreService.prototype = {
              !aTabState.userTypedValue);
   },
 
+  /**
+   * Determine if we can restore history into this tab.
+   * This will be false when a tab has been removed (usually between
+   * restoreHistoryPrecursor && restoreHistory) or if the tab is still marked
+   * as loading.
+   *
+   * @param aTab
+   * @returns boolean
+   */
+  _canRestoreTabHistory: function sss__canRestoreTabHistory(aTab) {
+    return aTab.parentNode && aTab.linkedBrowser &&
+           aTab.linkedBrowser.__SS_tabStillLoading;
+  },
+
   /**
    * This is going to take a state as provided at startup (via
    * nsISessionStartup.state) and split it into 2 parts. The first part