Preferences support for multiple promos.

chrome/browser/web_resource/notification_promo.h

Index: chrome/browser/web_resource/notification_promo.h
===================================================================
--- chrome/browser/web_resource/notification_promo.h	(revision 147894)
+++ chrome/browser/web_resource/notification_promo.h	(working copy)
@@ -27,6 +27,9 @@
  public:
   static GURL PromoServerURL();
 
+  static const char kNtpNotificationPromoType[];
+  static const char kBubblePromoType[];
+
   explicit NotificationPromo(Profile* profile);
   ~NotificationPromo();
 
@@ -79,6 +82,7 @@
   Profile* profile_;
   PrefService* prefs_;
 
+  std::string promo_type_;
   std::string promo_text_;
 #if defined(OS_ANDROID)
   std::string promo_text_long_;