Bug 802274 - Set the autostart pref when launching Firefox with the -private command line option; shoulder-r=jdm

browser/components/privatebrowsing/src/nsPrivateBrowsingService.js

@@ -466,6 +466,7 @@ PrivateBrowsingService.prototype = {
           if (this._autoStarted)
             aSubject.handleFlag("private", false);
 
+          Services.prefs.setBoolPref("browser.privatebrowsing.autostart", true);
           this.privateBrowsingEnabled = true;
           this._autoStarted = true;
           this._lastChangedByCommandLine = true;