Migrate upgrade notifications to observer

chrome/browser/ui/webui/settings/about_handler.cc

 // Copyright 2016 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/webui/settings/about_handler.h"
 
 #include <stddef.h>
 
 #include <string>
 
 #include "ash/system/devicetype_utils.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/i18n/message_formatter.h"
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task_scheduler/post_task.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
-#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/obsolete_system/obsolete_system.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/chrome_pages.h"
+#include "chrome/browser/upgrade_detector.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_content_client.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/google/core/browser/google_util.h"
 #include "components/policy/core/common/policy_namespace.h"
 #include "components/policy/policy_constants.h"
 #include "components/strings/grit/components_chromium_strings.h"
 #include "components/strings/grit/components_strings.h"
 #include "components/version_info/version_info.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/notification_service.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/browser/web_ui_data_source.h"
 #include "content/public/common/user_agent.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "v8/include/v8-version-string.h"
 
 #if defined(OS_CHROMEOS)
 #include "base/files/file_util_proxy.h"
 #include "base/i18n/time_formatting.h"
@@ skipping 319 matching lines @@
 
 #if defined(OS_CHROMEOS)
   // Handler for the product label image, which will be shown if available.
   content::URLDataSource::Add(Profile::FromWebUI(web_ui()),
                               new chromeos::ImageSource());
 #endif
 }
 
 void AboutHandler::OnJavascriptAllowed() {
   version_updater_.reset(VersionUpdater::Create(web_ui()->GetWebContents()));
-  registrar_.Add(this, chrome::NOTIFICATION_UPGRADE_RECOMMENDED,
-                 content::NotificationService::AllSources());
+  UpgradeDetector::GetInstance()->AddObserver(this);
   policy_registrar_.reset(new policy::PolicyChangeRegistrar(
       g_browser_process->policy_service(),
       policy::PolicyNamespace(policy::POLICY_DOMAIN_CHROME, std::string())));
   policy_registrar_->Observe(
       policy::key::kDeviceAutoUpdateDisabled,
       base::Bind(&AboutHandler::OnDeviceAutoUpdatePolicyChanged,
                  base::Unretained(this)));
 }
 
 void AboutHandler::OnJavascriptDisallowed() {

[sky, 2017/06/07 23:01:42]

Is there a guarantee that this is called before the destructor?

[weidongg, 2017/06/08 02:28:42]

I am not sure, but I moved AddObserver and RemoveObserver to constructor and
destructor, and use a flag to control real action.

   version_updater_.reset();
   policy_registrar_.reset();
-  registrar_.Remove(this, chrome::NOTIFICATION_UPGRADE_RECOMMENDED,
-                    content::NotificationService::AllSources());
+  UpgradeDetector::GetInstance()->RemoveObserver(this);
 }
 
-void AboutHandler::Observe(int type,
-                           const content::NotificationSource& source,
-                           const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_UPGRADE_RECOMMENDED, type);
-
+void AboutHandler::OnUpgradeRecommended() {
   // A version update is installed and ready to go. Refresh the UI so the
   // correct state will be shown.
   RequestUpdate();
 }
 
 void AboutHandler::OnDeviceAutoUpdatePolicyChanged(
     const base::Value* previous_policy,
     const base::Value* current_policy) {
   bool previous_auto_update_disabled = false;
   if (previous_policy)
@@ skipping 264 matching lines @@
       label_dir_path.AppendASCII(kRegulatoryLabelImageFilename).MaybeAsASCII();
   std::string url =
       std::string("chrome://") + chrome::kChromeOSAssetHost + "/" + image_path;
   regulatory_info->SetString("url", url);
 
   ResolveJavascriptCallback(base::Value(callback_id), *regulatory_info);
 }
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace settings