Remove dependency on NotificationService for cros a11y settings.

chrome/browser/ui/ash/system_tray_delegate_chromeos.cc

 // Copyright 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.
 
 #include "chrome/browser/ui/ash/system_tray_delegate_chromeos.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 257 matching lines @@
     registrar_->Add(this,
                     chrome::NOTIFICATION_SESSION_STARTED,
                     content::NotificationService::AllSources());
   }
   registrar_->Add(this,
                   chrome::NOTIFICATION_PROFILE_CREATED,
                   content::NotificationService::AllSources());
   registrar_->Add(this,
                   chrome::NOTIFICATION_PROFILE_DESTROYED,
                   content::NotificationService::AllSources());
-  registrar_->Add(
-      this,
-      chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_SCREEN_MAGNIFIER,
-      content::NotificationService::AllSources());
-  registrar_->Add(
-      this,
-      chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_SPOKEN_FEEDBACK,
-      content::NotificationService::AllSources());
-  registrar_->Add(
-      this,
-      chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_HIGH_CONTRAST_MODE,
-      content::NotificationService::AllSources());
-  registrar_->Add(
-      this,
-      chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_VIRTUAL_KEYBOARD,
-      content::NotificationService::AllSources());
+
+  AccessibilityManager* accessibility_manager = AccessibilityManager::Get();
+  CHECK(accessibility_manager);
+  accessibility_subscription_ = accessibility_manager->RegisterCallback(
+      base::Bind(&SystemTrayDelegateChromeOS::OnAccessibilityStatusChanged,
+                 base::Unretained(this)));

[sky, 2014/02/21 17:10:32]

Add a comment as to why Unretained is safe here.

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

The destructor for the subscription removes itself from the callback list.

 }
 
 void SystemTrayDelegateChromeOS::Initialize() {
   DBusThreadManager::Get()->GetSessionManagerClient()->AddObserver(this);
 
   input_method::InputMethodManager::Get()->AddObserver(this);
   ash::ime::InputMethodMenuManager::GetInstance()->AddObserver(this);
   UpdateClockType();
 
   if (SystemKeyEventListener::GetInstance())
@@ skipping 48 matching lines @@
 }
 
 SystemTrayDelegateChromeOS::~SystemTrayDelegateChromeOS() {
   // Unregister PrefChangeRegistrars.
   local_state_registrar_.reset();
   user_pref_registrar_.reset();
 
   // Unregister content notifications befure destroying any components.
   registrar_.reset();
 
+  // Unregister a11y status subscription.
+  accessibility_subscription_.reset();
+
   DBusThreadManager::Get()->GetSessionManagerClient()->RemoveObserver(this);
   input_method::InputMethodManager::Get()->RemoveObserver(this);
   ash::ime::InputMethodMenuManager::GetInstance()->RemoveObserver(this);
   if (SystemKeyEventListener::GetInstance())
     SystemKeyEventListener::GetInstance()->RemoveCapsLockObserver(this);
   bluetooth_adapter_->RemoveObserver(this);
   ash::Shell::GetInstance()
       ->session_state_delegate()
       ->RemoveSessionStateObserver(this);
   LoginState::Get()->RemoveObserver(this);
@@ skipping 783 matching lines @@
                            content::NotificationService::AllSources());
       }
       break;
     }
     case chrome::NOTIFICATION_SESSION_STARTED: {
       ash::Shell::GetInstance()->UpdateAfterLoginStatusChange(
           GetUserLoginStatus());
       SetProfile(ProfileManager::GetActiveUserProfile());
       break;
     }
-    case chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_SPOKEN_FEEDBACK:
-    case chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_HIGH_CONTRAST_MODE:
-    case chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_SCREEN_MAGNIFIER:
-    case chrome::NOTIFICATION_CROS_ACCESSIBILITY_TOGGLE_VIRTUAL_KEYBOARD: {
-      AccessibilityStatusEventDetails* accessibility_status =
-          content::Details<AccessibilityStatusEventDetails>(details).ptr();
-      OnAccessibilityModeChanged(accessibility_status->notify);
-      break;
-    }
     default:
       NOTREACHED();
   }
 }
 
 void SystemTrayDelegateChromeOS::OnLanguageRemapSearchKeyToChanged() {
   search_key_mapped_to_ = user_pref_registrar_->prefs()->GetInteger(
       prefs::kLanguageRemapSearchKeyTo);
 }
 
@@ skipping 140 matching lines @@
 void SystemTrayDelegateChromeOS::OnStoreError(policy::CloudPolicyStore* store) {
   UpdateEnterpriseDomain();
 }
 
 // Overridden from ash::SessionStateObserver
 void SystemTrayDelegateChromeOS::UserAddedToSession(
     const std::string& user_id) {
   GetSystemTrayNotifier()->NotifyUserAddedToSession();
 }
 
+void SystemTrayDelegateChromeOS::OnAccessibilityStatusChanged(
+    const AccessibilityStatusEventDetails& details) {
+  if (details.notification_type == ACCESSIBILITY_MANAGER_SHUTDOWN)
+    accessibility_subscription_.reset();
+  else
+    OnAccessibilityModeChanged(details.notify);
+}
+
 ash::SystemTrayDelegate* CreateSystemTrayDelegate() {
   return new SystemTrayDelegateChromeOS();
 }
 
 }  // namespace chromeos