Create TetherService, a TetherAllowed pref, and use DependencyManager for RegisterProfilePrefs call…

chrome/browser/tether/tether_service.cc

+// Copyright 2017 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/tether/tether_service.h"
+
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/memory/ptr_util.h"
+#include "build/build_config.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/chromeos/net/tether_notification_presenter.h"
+#include "chrome/browser/cryptauth/chrome_cryptauth_service_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
+#include "chrome/browser/tether/tether_service_factory.h"
+#include "chrome/common/pref_names.h"
+#include "chromeos/chromeos_switches.h"
+#include "chromeos/components/tether/initializer.h"
+#include "chromeos/network/network_connect.h"
+#include "chromeos/network/network_state_handler.h"
+#include "components/prefs/pref_service.h"
+#include "components/proximity_auth/logging/logging.h"
+#include "ui/message_center/message_center.h"
+
+// static
+TetherService* TetherService::Get(Profile* profile) {
+  return TetherServiceFactory::GetForBrowserContext(profile);
+}
+
+// static
+void TetherService::RegisterProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterBooleanPref(prefs::kTetherAllowed, true);
+  chromeos::tether::Initializer::RegisterProfilePrefs(registry);
+}
+
+TetherService::TetherService(Profile* profile)
+    : profile_(profile), shut_down_(false) {
+  registrar_.Init(profile_->GetPrefs());
+  registrar_.Add(
+      prefs::kTetherAllowed,
+      base::Bind(&TetherService::OnPrefsChanged, base::Unretained(this)));
+}
+
+TetherService::~TetherService() {}
+
+void TetherService::StartTether() {
+  // TODO (hansberry): Switch to using an IsEnabled() method.
+  if (!IsAllowed() || !base::CommandLine::ForCurrentProcess()->HasSwitch(
+                          chromeos::switches::kEnableTether)) {
+    return;
+  }
+
+  auto notification_presenter =
+      base::MakeUnique<chromeos::tether::TetherNotificationPresenter>(
+          message_center::MessageCenter::Get(),
+          chromeos::NetworkConnect::Get());
+  chromeos::tether::Initializer::Init(
+      ChromeCryptAuthServiceFactory::GetForBrowserContext(profile_),
+      std::move(notification_presenter), profile_->GetPrefs(),
+      ProfileOAuth2TokenServiceFactory::GetForProfile(profile_),
+      chromeos::NetworkHandler::Get()->network_state_handler(),
+      chromeos::NetworkConnect::Get());
+}
+
+bool TetherService::IsAllowed() const {
+  if (shut_down_)
+    return false;
+
+  if (!profile_->GetPrefs()->GetBoolean(prefs::kTetherAllowed))

[Kyle Horimoto, 2017/04/14 01:08:26]

Just return profile_->GetPrefs()->GetBoolean(prefs::kTetherAllowed) instead of
using if/else.

[Ryan Hansberry, 2017/04/14 02:34:10]

Done.

[Kyle Horimoto, 2017/04/14 18:39:20]

I think you forgot to upload your changes :)

[Ryan Hansberry, 2017/04/18 17:59:05]

Accidentally uploaded them to the CL depending on this, oops.

+    return false;
+
+  return true;
+}
+
+void TetherService::Shutdown() {
+  if (shut_down_)
+    return;
+
+  shut_down_ = true;
+  registrar_.RemoveAll();
+  chromeos::tether::Initializer::Shutdown();
+}
+
+void TetherService::OnPrefsChanged() {

[Kyle Horimoto, 2017/04/14 00:15:43]

What about if tethering is disabled, then reenabled? IsAllowed() will still
return false since shut_down_ == true.

[Ryan Hansberry, 2017/04/14 02:34:10]

Not sure I follow -- are you mixing up the Service being shutdown and
Initializer being shutdown? Initializer can be shutdown and re-initialized many
times within the lifetime of this service.

[Kyle Horimoto, 2017/04/14 18:39:20]

Yep, I was mixing it up. Thanks for the explanation!

+  // TODO (hansberry): Switch to using an IsEnabled() method.
+  if (IsAllowed() && base::CommandLine::ForCurrentProcess()->HasSwitch(
+                         chromeos::switches::kEnableTether)) {
+    StartTether();
+    return;
+  }
+
+  chromeos::tether::Initializer::Shutdown();
+}