Bug 676780 - Fennec is unable to load webpages and close tabs (corrupt sessionstore) [r=mbrubeck]

mobile/chrome/content/browser.js

@@ -355,10 +355,12 @@ var Browser = {
         // Initial window resizes call functions that assume a tab is in the tab list
         // and restored tabs are added too late. We add a dummy to to satisfy the resize
         // code and then remove the dummy after the session has been restored.
-        let dummy = this.addTab("about:blank");
+        let dummy = this.addTab("about:blank", true);
         let dummyCleanup = {
-          observe: function() {
+          observe: function(aSubject, aTopic, aData) {
             Services.obs.removeObserver(dummyCleanup, "sessionstore-windows-restored");
+            if (aData == "fail")
+              Browser.addTab(commandURL || Browser.getHomePage(), true);
             dummy.chromeTab.ignoreUndo = true;
             Browser.closeTab(dummy, { forceClose: true });
           }

mobile/components/SessionStore.js

@@ -707,14 +707,16 @@ SessionStore.prototype = {
   },
 
   restoreLastSession: function ss_restoreLastSession(aBringToFront) {
-    // The previous session data has already been renamed to the backup file
-    if (!this._sessionFileBackup.exists())
-      return;
-
     let self = this;
-    function notifyObservers() {
+    function notifyObservers(aMessage) {
       self._clearCache();
-      Services.obs.notifyObservers(null, "sessionstore-windows-restored", "");
+      Services.obs.notifyObservers(null, "sessionstore-windows-restored", aMessage || "");
+    }
+
+    // The previous session data has already been renamed to the backup file
+    if (!this._sessionFileBackup.exists()) {
+      notifyObservers("fail")
+      return;
     }
 
     try {
@@ -723,7 +725,7 @@ SessionStore.prototype = {
       NetUtil.asyncFetch(channel, function(aStream, aResult) {
         if (!Components.isSuccessCode(aResult)) {
           Cu.reportError("SessionStore: Could not read from sessionstore.bak file");
-          notifyObservers();
+          notifyObservers("fail");
           return;
         }
 
@@ -742,14 +744,17 @@ SessionStore.prototype = {
         }
 
         if (!data || data.windows.length == 0) {
-          notifyObservers();
+          notifyObservers("fail");
           return;
         }
 
         let window = Services.wm.getMostRecentWindow("navigator:browser");
 
-        let selected = data.windows[0].selected;
         let tabs = data.windows[0].tabs;
+        let selected = data.windows[0].selected;
+        if (selected > tabs.length) // Clamp the selected index if it's bogus
+          selected = 1;
+
         for (let i=0; i<tabs.length; i++) {
           let tabData = tabs[i];
 
@@ -795,7 +800,7 @@ SessionStore.prototype = {
       });
     } catch (ex) {
       Cu.reportError("SessionStore: Could not read from sessionstore.bak file: " + ex);
-      notifyObservers();
+      notifyObservers("fail");
     }
   }
 };