Factor Google Now welcome notifications out of DesktopNotificationService.

chrome/browser/notifications/extensions/extension_welcome_notification.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_NOTIFICATIONS_EXTENSION_WELCOME_NOTIFICATION_H_
-#define CHROME_BROWSER_NOTIFICATIONS_EXTENSION_WELCOME_NOTIFICATION_H_
+#ifndef CHROME_BROWSER_NOTIFICATIONS_EXTENSIONS_EXTENSION_WELCOME_NOTIFICATION_H_
+#define CHROME_BROWSER_NOTIFICATIONS_EXTENSIONS_EXTENSION_WELCOME_NOTIFICATION_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/pref_member.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/prefs/pref_service_syncable_observer.h"
+#include "components/keyed_service/core/keyed_service.h"
 #include "ui/message_center/notifier_settings.h"
 
 namespace base {
 typedef Callback<void(void)> Closure;
 }
 
 namespace message_center {
 class MessageCenter;
 }
 
 namespace tracked_objects {
 class Location;
 }
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 class Notification;
 class Profile;
 
-// ExtensionWelcomeNotification is a part of DesktopNotificationService and
-// manages showing and hiding a welcome notification for built-in components
-// that show notifications. The Welcome Notification presumes network
-// connectivity since it relies on synced preferences to work. This is generally
-// fine since the current consumers on the welcome notification also presume
-// network connectivity.
+// ExtensionWelcomeNotification is a keyed service which manages showing and
+// hiding a welcome notification for built-in components which show

[robliao, 2014/09/18 20:10:01]

Nit: s/which/that

The first clause is non-restrictive, so 'which' works. The
ExtensionWelcomeNotification is indeed a KeyedService.

The second clause is restrictive. The ExtensionWelcomeNotification only manages
the welcome notification for built-in components that show notifications, not
all built-in components.

[Peter Beverloo, 2014/09/19 13:01:22]

Insightful, thanks :-).

+// notifications. The Welcome Notification presumes network connectivity since
+// it relies on synced preferences to work. This is generally fine since the
+// current consumers on the welcome notification also presume network
+// connectivity.
+//
 // This class expects to be created and called from the UI thread.
-class ExtensionWelcomeNotification : public PrefServiceSyncableObserver {
+class ExtensionWelcomeNotification : public KeyedService,
+                                     public PrefServiceSyncableObserver {
  public:
   // Allows for overriding global calls.
   class Delegate {
    public:
     Delegate() {}
     virtual ~Delegate() {}
     virtual message_center::MessageCenter* GetMessageCenter() = 0;
     virtual base::Time GetCurrentTime() = 0;
     virtual void PostTask(
         const tracked_objects::Location& from_here,
         const base::Closure& task) = 0;
    private:
     DISALLOW_COPY_AND_ASSIGN(Delegate);
   };
 
   // Requested time from showing the welcome notification to expiration.
   static const int kRequestedShowTimeDays;
 
+  // The extension Id associated with the Google Now extension.
+  static const char kChromeNowExtensionID[];
+
   virtual ~ExtensionWelcomeNotification();
 
   // To workaround the lack of delegating constructors prior to C++11, we use
   // static Create methods.
-  // Creates an ExtensionWelcomeNotification owned by the specified
-  // extension id with the default delegate.
+  // Creates an ExtensionWelcomeNotification with the default delegate.
   static scoped_ptr<ExtensionWelcomeNotification> Create(
-      const std::string& extension_id,
       Profile* const profile);
 
-  // Creates an ExtensionWelcomeNotification owned by the specified
-  // extension id with the specified delegate.
+  // Creates an ExtensionWelcomeNotification with the specified delegate.
   static scoped_ptr<ExtensionWelcomeNotification> Create(
-      const std::string& extension_id,
       Profile* const profile,
       Delegate* const delegate);
 
   // PrefServiceSyncableObserver
   virtual void OnIsSyncingChanged() OVERRIDE;
 
   // Adds in the welcome notification if required for components built
   // into Chrome that show notifications like Chrome Now.
   void ShowWelcomeNotificationIfNecessary(const Notification& notification);
 
   // Handles Preference Registration for the Welcome Notification.
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* prefs);
 
  private:
   enum PopUpRequest { POP_UP_HIDDEN = 0, POP_UP_SHOWN = 1, };
 
   ExtensionWelcomeNotification(
-      const std::string& extension_id,
       Profile* const profile,
       ExtensionWelcomeNotification::Delegate* const delegate);
 
   // Gets the message center from the delegate.
   message_center::MessageCenter* GetMessageCenter() const;
 
   // Unconditionally shows the welcome notification.
   void ShowWelcomeNotification(const base::string16& display_source,
                                const PopUpRequest pop_up_request);
 
@@ skipping 52 matching lines @@
   scoped_ptr<base::OneShotTimer<ExtensionWelcomeNotification> >
       expiration_timer_;
 
   // Delegate for Chrome global calls like base::Time::GetTime() for
   // testability.
   scoped_ptr<Delegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionWelcomeNotification);
 };
 
-#endif  // CHROME_BROWSER_NOTIFICATIONS_EXTENSION_WELCOME_NOTIFICATION_H_
+#endif  // CHROME_BROWSER_NOTIFICATIONS_EXTENSIONS_EXTENSION_WELCOME_NOTIFICATION_H_