Backout changeset 9ab865986f27 for bug 481786 in order to get a ui-review on that

browser/components/sessionstore/src/nsSessionStartup.js

@@ -43,8 +43,7 @@
 # * Overview
 # * This service reads user's session file at startup, and makes a determination 
 # * as to whether the session should be restored. It will restore the session 
-# * under the circumstances described below.  If the auto-start Private Browsing
-# * mode is active, however, the session is never restored.
+# * under the circumstances described below.
 # * 
 # * Crash Detection
 # * The session file stores a session.state property, that 
@@ -96,12 +95,6 @@ SessionStartup.prototype = {
    * Initialize the component
    */
   init: function sss_init() {
-    // do not need to initialize anything in auto-started private browsing sessions
-    let pbs = Cc["@mozilla.org/privatebrowsing;1"].
-              getService(Ci.nsIPrivateBrowsingService);
-    if (pbs.autoStarted)
-      return;
-
     let prefBranch = Cc["@mozilla.org/preferences-service;1"].
                      getService(Ci.nsIPrefService).getBranch("browser.");
 

browser/components/sessionstore/src/nsSessionStore.js

@@ -415,9 +415,7 @@ SessionStoreService.prototype = {
       case "exit":
         aSubject.QueryInterface(Ci.nsISupportsPRBool);
         let quitting = aSubject.data;
-        let pbs = Cc["@mozilla.org/privatebrowsing;1"].
-                  getService(Ci.nsIPrivateBrowsingService);
-        if (quitting && !pbs.autoStarted) {
+        if (quitting) {
           // save the backed up state with session set to stopped,
           // otherwise resuming next time would look like a crash
           if ("_stateBackup" in this) {