Remove dependency on NotificationService for cros a11y settings.

chrome/browser/chromeos/accessibility/accessibility_manager.h

 // Copyright (c) 2013 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_CHROMEOS_ACCESSIBILITY_ACCESSIBILITY_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_ACCESSIBILITY_ACCESSIBILITY_MANAGER_H_
 
 #include <set>
 
 #include "ash/accessibility_delegate.h"
 #include "ash/session_state_observer.h"
+#include "base/callback_list.h"
 #include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "base/time/time.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_util.h"
 #include "chrome/browser/extensions/api/braille_display_private/braille_controller.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "extensions/browser/event_router.h"
 #include "extensions/browser/extension_system.h"
 
 namespace content {
 class RenderViewHost;
 }
 class Profile;
 
 namespace chromeos {
 
+enum AccessibilityNotificationType {
+  ACCESSIBILITY_MANAGER_SHUTDOWN,
+  ACCESSIBILITY_TOGGLE_HIGH_CONTRAST_MODE,
+  ACCESSIBILITY_TOGGLE_LARGE_CURSOR,
+  ACCESSIBILITY_TOGGLE_SCREEN_MAGNIFIER,
+  ACCESSIBILITY_TOGGLE_SPOKEN_FEEDBACK,
+  ACCESSIBILITY_TOGGLE_VIRTUAL_KEYBOARD
+};
+
 struct AccessibilityStatusEventDetails {
   AccessibilityStatusEventDetails(
+      AccessibilityNotificationType notification_type,
       bool enabled,
       ash::AccessibilityNotificationVisibility notify);
 
   AccessibilityStatusEventDetails(
+      AccessibilityNotificationType notification_type,
       bool enabled,
       ash::MagnifierType magnifier_type,
       ash::AccessibilityNotificationVisibility notify);
 
+  AccessibilityNotificationType notification_type;
   bool enabled;
   ash::MagnifierType magnifier_type;
   ash::AccessibilityNotificationVisibility notify;
 };
 
+typedef base::Callback<void(const AccessibilityStatusEventDetails&)>
+    AccessibilityStatusCallback;
+
+typedef base::CallbackList<void(const AccessibilityStatusEventDetails&)>
+    AccessibilityStatusCallbackList;
+
+typedef AccessibilityStatusCallbackList::Subscription
+    AccessibilityStatusSubscription;
+
 // AccessibilityManager changes the statuses of accessibility features
 // watching profile notifications and pref-changes.
 // TODO(yoshiki): merge MagnificationManager with AccessibilityManager.
 class AccessibilityManager : public content::NotificationObserver,
     extensions::api::braille_display_private::BrailleObserver,
     public ash::SessionStateObserver {
  public:
   // Creates an instance of AccessibilityManager, this should be called once,
   // because only one instance should exist at the same time.
   static void Initialize();
@@ skipping 83 matching lines @@
 
   // Enables/disables system sounds.
   void EnableSystemSounds(bool system_sounds_enabled);
 
   // Initiates play of shutdown sound and returns it's duration.
   base::TimeDelta PlayShutdownSound();
 
   // Injects ChromeVox scripts into given |render_view_host|.
   void InjectChromeVox(content::RenderViewHost* render_view_host);
 
+  // Register a callback to be notified when the status of an accessibility
+  // option changes.
+  scoped_ptr<AccessibilityStatusSubscription> RegisterCallback(
+      const AccessibilityStatusCallback& cb);
+
+  // Notify registered callbacks of a status change in an accessibility setting.
+  void NotifyAccessibilityStatusChanged(
+      AccessibilityStatusEventDetails& details);
+
  protected:
   AccessibilityManager();
   virtual ~AccessibilityManager();
 
  private:
   void LoadChromeVox();
   void LoadChromeVoxToUserScreen();
   void LoadChromeVoxToLockScreen();
   void UnloadChromeVox();
   void UnloadChromeVoxFromLockScreen();
   void PostLoadChromeVox(Profile* profile);
   void PostUnloadChromeVox(Profile* profile);
 
   void UpdateLargeCursorFromPref();
   void UpdateStickyKeysFromPref();
   void UpdateSpokenFeedbackFromPref();
   void UpdateHighContrastFromPref();
   void UpdateAutoclickFromPref();
   void UpdateAutoclickDelayFromPref();
   void UpdateVirtualKeyboardFromPref();
   void LocalePrefChanged();
 
   void CheckBrailleState();
   void ReceiveBrailleDisplayState(
       scoped_ptr<extensions::api::braille_display_private::DisplayState> state);
 
-
   void SetProfile(Profile* profile);
 
   void UpdateChromeOSAccessibilityHistograms();
 
   // content::NotificationObserver implementation:
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // extensions::api::braille_display_private::BrailleObserver implementation.
@@ skipping 31 matching lines @@
   bool virtual_keyboard_enabled_;
 
   ash::AccessibilityNotificationVisibility spoken_feedback_notification_;
 
   base::WeakPtrFactory<AccessibilityManager> weak_ptr_factory_;
 
   bool should_speak_chrome_vox_announcements_on_user_screen_;
 
   bool system_sounds_enabled_;
 
+  AccessibilityStatusCallbackList callback_list_;

[David Tseng, 2014/02/21 17:42:59]

I'm unclear as to the ownership of this list. It's returned by RegisterCallback
and appears to be reset by external classes?

[kevers, 2014/02/21 17:52:31]

External classes reset/cancel their subscriptions when deleted. Subscribers are
also told when the accessibility manager is being shut down so that they can
release their subscriptions, which alleviates potential ordering problems on
shutdown.

[David Tseng, 2014/02/21 19:44:51]

Ok; thanks for clarifying.

+
   DISALLOW_COPY_AND_ASSIGN(AccessibilityManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_ACCESSIBILITY_ACCESSIBILITY_MANAGER_H_