When app shortcuts are enabled, do a once-off creation of all shortcuts.

apps/shortcut_manager.h

Index: apps/shortcut_manager.h
diff --git a/apps/shortcut_manager.h b/apps/shortcut_manager.h
index a0efb822c183728afce6f717285a99238dccfffa..b654053c778e8db73f179e67ae904b9a491070b7 100644
--- a/apps/shortcut_manager.h
+++ b/apps/shortcut_manager.h
@@ -11,6 +11,7 @@
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
+class PrefService;
 class Profile;
 
 namespace apps {
@@ -29,10 +30,15 @@ class ShortcutManager : public BrowserContextKeyedService,
                        const content::NotificationDetails& details) OVERRIDE;
 
  private:
+  // Checks if kShortcutsEnabled is set in prefs. If not, this sets it and
+  // creates shortcuts for all apps.
+  void OnceOffCreateShortcuts();
+
   void DeleteApplicationShortcuts(const extensions::Extension* extension);
 
   content::NotificationRegistrar registrar_;
   Profile* profile_;
+  PrefService* prefs_;
 
   // Fields used when installing application shortcuts.
   base::WeakPtrFactory<ShortcutManager> weak_factory_;