chrome/browser/web_resource/promo_resource_service.h

   1 // Copyright 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_WEB_RESOURCE_PROMO_RESOURCE_SERVICE_H_
   6 #define CHROME_BROWSER_WEB_RESOURCE_PROMO_RESOURCE_SERVICE_H_
   7
   8 #include <string>
   9
  10 #include "base/callback_forward.h"
  11 #include "base/callback_list.h"
  12 #include "base/memory/weak_ptr.h"
  13 #include "chrome/browser/web_resource/chrome_web_resource_service.h"
  14
  15 class NotificationPromo;
  16 class PrefRegistrySimple;
  17 class PrefService;
  18
  19 namespace base {
  20 class DictionaryValue;
  21 }
  22
  23 namespace user_prefs {
  24 class PrefRegistrySyncable;
  25 }
  26
  27 // A PromoResourceService fetches data from a web resource server to be used to
  28 // dynamically change the appearance of the New Tab Page. For example, it has
  29 // been used to fetch "tips" to be displayed on the NTP, or to display
  30 // promotional messages to certain groups of Chrome users.
  31 class PromoResourceService : public ChromeWebResourceService {
  32  public:
  33   using StateChangedCallbackList = base::CallbackList<void()>;
  34   using StateChangedSubscription = StateChangedCallbackList::Subscription;
  35
  36   static void RegisterPrefs(PrefRegistrySimple* registry);
  37   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
  38   static void MigrateUserPrefs(PrefService* user_prefs);
  39
  40   PromoResourceService();
  41   ~PromoResourceService() override;
  42
  43   // Registers a callback called when the state of a web resource has been
  44   // changed. A resource may have been added, removed, or altered.
  45   scoped_ptr<StateChangedSubscription> RegisterStateChangedCallback(
  46       const base::Closure& closure);
  47
  48  private:
  49   // Schedule a notification that a web resource is either going to become
  50   // available or be no longer valid.
  51   void ScheduleNotification(const NotificationPromo& notification_promo);
  52
  53   // Schedules the initial notification for when the web resource is going
  54   // to become available or no longer valid. This performs a few additional
  55   // checks than ScheduleNotification, namely it schedules updates immediately
  56   // if the promo service or Chrome locale has changed.
  57   void ScheduleNotificationOnInit();
  58
  59   // If delay_ms is positive, schedule notification with the delay.
  60   // If delay_ms is 0, notify immediately by calling WebResourceStateChange().
  61   // If delay_ms is negative, do nothing.
  62   void PostNotification(int64 delay_ms);
  63
  64   // Notify listeners that the state of a web resource has changed.
  65   void PromoResourceStateChange();
  66
  67   // WebResourceService override to process the parsed information.
  68   void Unpack(const base::DictionaryValue& parsed_json) override;
  69
  70   // List of callbacks called when the state of a web resource has changed.
  71   StateChangedCallbackList callback_list_;
  72
  73   // Allows the creation of tasks to send a notification.
  74   // This allows the PromoResourceService to notify the New Tab Page immediately
  75   // when a new web resource should be shown or removed.
  76   base::WeakPtrFactory<PromoResourceService> weak_ptr_factory_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(PromoResourceService);
  79 };
  80
  81 #endif  // CHROME_BROWSER_WEB_RESOURCE_PROMO_RESOURCE_SERVICE_H_