Use WeakPtr in VersionUpdaterCros for safety

chrome/browser/ui/webui/help/version_updater_chromeos.cc

 // Copyright (c) 2012 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/help/version_updater_chromeos.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "chrome/browser/chromeos/cros_settings.h"
 #include "chrome/browser/chromeos/cros_settings_names.h"
@@ skipping 16 matching lines @@
   callback_ = callback;
 
   UpdateEngineClient* update_engine_client =
       DBusThreadManager::Get()->GetUpdateEngineClient();
   update_engine_client->AddObserver(this);
 
   // Make sure that libcros is loaded and OOBE is complete.
   if (!WizardController::default_controller() ||
       WizardController::IsDeviceRegistered()) {
     update_engine_client->RequestUpdateCheck(
-        base::Bind(&VersionUpdaterCros::OnUpdateCheck, base::Unretained(this)));
+        base::Bind(&VersionUpdaterCros::OnUpdateCheck,
+                   weak_ptr_factory_.GetWeakPtr()));
   }
 }
 
 void VersionUpdaterCros::RelaunchBrowser() const {
   DBusThreadManager::Get()->GetPowerManagerClient()->RequestRestart();
 }
 
 void VersionUpdaterCros::SetReleaseChannel(const std::string& channel) {
   DBusThreadManager::Get()->GetUpdateEngineClient()->SetReleaseTrack(channel);
   // For local owner set the field in the policy blob too.
   if (UserManager::Get()->IsCurrentUserOwner())
     CrosSettings::Get()->SetString(chromeos::kReleaseChannel, channel);
 }
 
 void VersionUpdaterCros::GetReleaseChannel(const ChannelCallback& cb) {
   channel_callback_ = cb;
 
   // TODO(jhawkins): Store on this object.
   UpdateEngineClient* update_engine_client =
       DBusThreadManager::Get()->GetUpdateEngineClient();
 
   // Request the channel information. Use the observer to track the help page
   // handler and ensure it does not get deleted before the callback.
   update_engine_client->GetReleaseTrack(
       base::Bind(&VersionUpdaterCros::UpdateSelectedChannel,
-                 base::Unretained(this)));
+                 weak_ptr_factory_.GetWeakPtr()));
 }
 
-VersionUpdaterCros::VersionUpdaterCros() {}
+VersionUpdaterCros::VersionUpdaterCros() : weak_ptr_factory_(this) {}
 
 VersionUpdaterCros::~VersionUpdaterCros() {
   UpdateEngineClient* update_engine_client =
       DBusThreadManager::Get()->GetUpdateEngineClient();
   update_engine_client->RemoveObserver(this);
 }
 
 void VersionUpdaterCros::UpdateStatusChanged(
     const UpdateEngineClient::Status& status) {
   Status my_status = UPDATED;
@@ skipping 31 matching lines @@
     UpdateEngineClient::UpdateCheckResult result) {
   // If version updating is not implemented, this binary is the most up-to-date
   // possible with respect to automatic updating.
   if (result == UpdateEngineClient::UPDATE_RESULT_NOTIMPLEMENTED)
     callback_.Run(UPDATED, 0, string16());
 }
 
 void VersionUpdaterCros::UpdateSelectedChannel(const std::string& channel) {
   channel_callback_.Run(channel);
 }