chromeos: Replace user image notifications with observer

components/user_manager/user_manager.cc

 // 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.
 
 #include "components/user_manager/user_manager.h"
 
 #include "base/logging.h"
 #include "components/signin/core/account_id/account_id.h"
 
 namespace user_manager {
 
-UserManager* UserManager::instance = NULL;
+UserManager* UserManager::instance = nullptr;
 
-UserManager::Observer::~Observer() {
-}
+UserManager::Observer::~Observer() = default;
 
-void UserManager::Observer::LocalStateChanged(UserManager* user_manager) {
-}
+void UserManager::Observer::LocalStateChanged(UserManager* user_manager) {}
+
+void UserManager::Observer::OnUserImageChanged(const User& user) {}
+
+void UserManager::Observer::OnUserProfileImageUpdateFailed(const User& user) {}
+
+void UserManager::Observer::OnUserProfileImageUpdated(
+    const User& user,
+    const gfx::ImageSkia& profile_image) {}
 
 void UserManager::UserSessionStateObserver::ActiveUserChanged(
     const User* active_user) {
 }
 
 void UserManager::UserSessionStateObserver::UserAddedToSession(
     const User* active_user) {
 }
 
 void UserManager::UserSessionStateObserver::ActiveUserHashChanged(
@@ skipping 21 matching lines @@
   UserManager::SetInstance(this);
 }
 
 // static
 bool UserManager::IsInitialized() {
   return UserManager::instance;
 }
 
 void UserManager::Destroy() {
   DCHECK(UserManager::instance == this);
-  UserManager::SetInstance(NULL);
+  UserManager::SetInstance(nullptr);
 }
 
 // static
 UserManager* user_manager::UserManager::Get() {
   CHECK(UserManager::instance);
   return UserManager::instance;
 }
 
 UserManager::~UserManager() {
 }
 
 // static
 void UserManager::SetInstance(UserManager* user_manager) {
   UserManager::instance = user_manager;
 }
 
 // static
 UserManager* user_manager::UserManager::GetForTesting() {
   return UserManager::instance;
 }
 
 // static
 UserManager* UserManager::SetForTesting(UserManager* user_manager) {
   UserManager* previous_instance = UserManager::instance;
   UserManager::instance = user_manager;
   return previous_instance;
 }
 
 }  // namespace user_manager