Massively simplify the NetworkChangeNotifier infrastructure:

  * Use a process-wide object (singleton pattern)
  * Create/destroy this object on the main thread, make it outlive all consumers
  * Make observer-related functions threadsafe

As a result, the notifier can now be used by any thread (eliminating things like NetworkChangeObserverProxy and NetworkChangeNotifierProxy, and expanding its usefulness); its creation and inner workings are much simplified (eliminating implementation-specific classes); and it is simpler to access (eliminating things like NetworkChangeNotifierThread and a LOT of passing pointers around).

BUG=none
TEST=Unittests; network changes still trigger notifications
Review URL: http://codereview.chromium.org/2802015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50895 0039d316-1c4b-4281-b951-d872f2087c98

16 files changed, 37 insertions, 303 deletions

diff --git a/chrome/browser/sync/engine/syncapi.cc b/chrome/browser/sync/engine/syncapi.cc
index e970c81..1012bf7 100644
--- a/chrome/browser/sync/engine/syncapi.cc
+++ b/chrome/browser/sync/engine/syncapi.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -54,7 +54,6 @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/deprecated/event_sys.h"
 #include "chrome/common/net/gaia/gaia_authenticator.h"
-#include "chrome/common/net/network_change_notifier_proxy.h"
 #include "chrome/common/net/notifier/listener/mediator_thread_impl.h"
 #include "chrome/common/net/notifier/listener/notification_constants.h"
 #include "chrome/common/net/notifier/listener/talk_mediator.h"
@@ -883,8 +882,6 @@ class SyncManager::SyncInternal
             const char* gaia_service_id,
             const char* gaia_source,
             bool use_ssl,
-            chrome_common_net::NetworkChangeNotifierThread*
-                network_change_notifier_thread,
             HttpPostProviderFactory* post_factory,
             HttpPostProviderFactory* auth_post_factory,
             ModelSafeWorkerRegistrar* model_safe_worker_registrar,
@@ -1166,10 +1163,6 @@ class SyncManager::SyncInternal
   // The sync dir_manager to which we belong.
   SyncManager* const sync_manager_;
 
-  // An object that notifies us whenever there is a network-related
-  // change (e.g., disconnections).
-  scoped_ptr<net::NetworkChangeNotifier> network_change_notifier_;
-
   // The entity that provides us with information about which types to sync.
   // The instance is shared between the SyncManager and the Syncer.
   ModelSafeWorkerRegistrar* registrar_;
@@ -1201,8 +1194,6 @@ bool SyncManager::Init(const FilePath& database_location,
                        const char* gaia_service_id,
                        const char* gaia_source,
                        bool use_ssl,
-                       chrome_common_net::NetworkChangeNotifierThread*
-                           network_change_notifier_thread,
                        HttpPostProviderFactory* post_factory,
                        HttpPostProviderFactory* auth_post_factory,
                        ModelSafeWorkerRegistrar* registrar,
@@ -1221,7 +1212,6 @@ bool SyncManager::Init(const FilePath& database_location,
                      gaia_service_id,
                      gaia_source,
                      use_ssl,
-                     network_change_notifier_thread,
                      post_factory,
                      auth_post_factory,
                      registrar,
@@ -1271,8 +1261,6 @@ bool SyncManager::SyncInternal::Init(
     const char* gaia_service_id,
     const char* gaia_source,
     bool use_ssl,
-    chrome_common_net::NetworkChangeNotifierThread*
-        network_change_notifier_thread,
     HttpPostProviderFactory* post_factory,
     HttpPostProviderFactory* auth_post_factory,
     ModelSafeWorkerRegistrar* model_safe_worker_registrar,
@@ -1310,29 +1298,22 @@ bool SyncManager::SyncInternal::Init(
   // Watch various objects for aggregated status.
   allstatus_.WatchConnectionManager(connection_manager());
 
-  network_change_notifier_.reset(
-      new chrome_common_net::NetworkChangeNotifierProxy(
-          network_change_notifier_thread));
-  network_change_notifier_->AddObserver(this);
-  // TODO(akalin): CheckServerReachable() can block, which may cause
-  // jank if we try to shut down sync.  Fix this.
+  net::NetworkChangeNotifier::AddObserver(this);
+  // TODO(akalin): CheckServerReachable() can block, which may cause jank if we
+  // try to shut down sync.  Fix this.
   connection_manager()->CheckServerReachable();
 
-  // NOTIFICATION_SERVER uses a substantially different notification
-  // method, so it has its own MediatorThread implementation.
-  // Everything else just uses MediatorThreadImpl.
+  // NOTIFICATION_SERVER uses a substantially different notification method, so
+  // it has its own MediatorThread implementation.  Everything else just uses
+  // MediatorThreadImpl.
   notifier::MediatorThread* mediator_thread =
       (notification_method == browser_sync::NOTIFICATION_SERVER) ?
-      static_cast<notifier::MediatorThread*>(
-          new sync_notifier::ServerNotifierThread(
-              network_change_notifier_thread)) :
-      static_cast<notifier::MediatorThread*>(
-          new notifier::MediatorThreadImpl(network_change_notifier_thread));
+      new sync_notifier::ServerNotifierThread() :
+      new notifier::MediatorThreadImpl();
   const bool kInitializeSsl = true;
   const bool kConnectImmediately = false;
-  talk_mediator_.reset(new TalkMediatorImpl(
-      mediator_thread,
-      kInitializeSsl, kConnectImmediately, invalidate_xmpp_auth_token));
+  talk_mediator_.reset(new TalkMediatorImpl(mediator_thread, kInitializeSsl,
+      kConnectImmediately, invalidate_xmpp_auth_token));
   if (notification_method != browser_sync::NOTIFICATION_LEGACY &&
       notification_method != browser_sync::NOTIFICATION_SERVER) {
     if (notification_method == browser_sync::NOTIFICATION_TRANSITIONAL) {
@@ -1595,10 +1576,7 @@ void SyncManager::SyncInternal::Shutdown() {
     core_message_loop_->SetNestableTasksAllowed(old_state);
   }
 
-  if (network_change_notifier_.get()) {
-    network_change_notifier_->RemoveObserver(this);
-    network_change_notifier_.reset();
-  }
+  net::NetworkChangeNotifier::RemoveObserver(this);
 
   if (dir_manager()) {
     dir_manager()->FinalSaveChangesForAll();
diff --git a/chrome/browser/sync/engine/syncapi.h b/chrome/browser/sync/engine/syncapi.h
index 88b2f0b..c9380e5 100644
--- a/chrome/browser/sync/engine/syncapi.h
+++ b/chrome/browser/sync/engine/syncapi.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -60,10 +60,6 @@ struct SyncSessionSnapshot;
 }
 }
 
-namespace chrome_common_net {
-class NetworkChangeNotifierThread;
-}
-
 // Forward declarations of internal class types so that sync API objects
 // may have opaque pointers to these types.
 namespace syncable {
@@ -710,9 +706,6 @@ class SyncManager {
   // the default is false.
   // |gaia_service_id| is the service id used for GAIA authentication. If it's
   // null then default will be used.
-  // |network_change_notifier_thread| (which we don't own) is the
-  // thread from which we get notifications regarding changes to the
-  // network state.
   // |post_factory| will be owned internally and used to create
   // instances of an HttpPostProvider.
   // |auth_post_factory| will be owned internally and used to create
@@ -745,8 +738,6 @@ class SyncManager {
             const char* gaia_service_id,
             const char* gaia_source,
             bool use_ssl,
-            chrome_common_net::NetworkChangeNotifierThread*
-                network_change_notifier_thread,
             HttpPostProviderFactory* post_factory,
             HttpPostProviderFactory* auth_post_factory,
             browser_sync::ModelSafeWorkerRegistrar* registrar,
diff --git a/chrome/browser/sync/glue/sync_backend_host.cc b/chrome/browser/sync/glue/sync_backend_host.cc
index 0c36f3d..7428245 100644
--- a/chrome/browser/sync/glue/sync_backend_host.cc
+++ b/chrome/browser/sync/glue/sync_backend_host.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -67,8 +67,6 @@ SyncBackendHost::~SyncBackendHost() {
 void SyncBackendHost::Initialize(
     const GURL& sync_service_url,
     const syncable::ModelTypeSet& types,
-    chrome_common_net::NetworkChangeNotifierThread*
-        network_change_notifier_thread,
     URLRequestContextGetter* baseline_context_getter,
     const std::string& lsid,
     bool delete_sync_data_folder,
@@ -107,7 +105,6 @@ void SyncBackendHost::Initialize(
       NewRunnableMethod(core_.get(), &SyncBackendHost::Core::DoInitialize,
                         Core::DoInitializeOptions(
                             sync_service_url, true,
-                            network_change_notifier_thread,
                             new HttpBridgeFactory(baseline_context_getter),
                             new HttpBridgeFactory(baseline_context_getter),
                             lsid,
@@ -392,7 +389,6 @@ void SyncBackendHost::Core::DoInitialize(const DoInitializeOptions& options) {
       kGaiaServiceId,
       kGaiaSourceForChrome,
       options.service_url.SchemeIsSecure(),
-      options.network_change_notifier_thread,
       options.http_bridge_factory,
       options.auth_http_bridge_factory,
       host_,  // ModelSafeWorkerRegistrar.
diff --git a/chrome/browser/sync/glue/sync_backend_host.h b/chrome/browser/sync/glue/sync_backend_host.h
index be20013..0193163 100644
--- a/chrome/browser/sync/glue/sync_backend_host.h
+++ b/chrome/browser/sync/glue/sync_backend_host.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -29,10 +29,6 @@
 class CancelableTask;
 class Profile;
 
-namespace chrome_common_net {
-class NetworkChangeNotifierThread;
-}
-
 namespace browser_sync {
 
 namespace sessions {
@@ -100,8 +96,6 @@ class SyncBackendHost : public browser_sync::ModelSafeWorkerRegistrar {
   // Optionally delete the Sync Data folder (if it's corrupt).
   void Initialize(const GURL& service_url,
                   const syncable::ModelTypeSet& types,
-                  chrome_common_net::NetworkChangeNotifierThread*
-                      network_change_notifier_thread,
                   URLRequestContextGetter* baseline_context_getter,
                   const std::string& lsid,
                   bool delete_sync_data_folder,
@@ -180,8 +174,6 @@ class SyncBackendHost : public browser_sync::ModelSafeWorkerRegistrar {
   // Called from unit test to bypass authentication and initialize the syncapi
   // to a state suitable for testing but not production.
   void InitializeForTestMode(const std::wstring& test_user,
-                             chrome_common_net::NetworkChangeNotifierThread*
-                                 network_change_notifier_thread,
                              sync_api::HttpPostProviderFactory* factory,
                              sync_api::HttpPostProviderFactory* auth_factory,
                              bool delete_sync_data_folder,
@@ -201,7 +193,6 @@ class SyncBackendHost : public browser_sync::ModelSafeWorkerRegistrar {
         NewRunnableMethod(core_.get(),
         &SyncBackendHost::Core::DoInitializeForTest,
         test_user,
-        network_change_notifier_thread,
         factory,
         auth_factory,
         delete_sync_data_folder,
@@ -237,8 +228,6 @@ class SyncBackendHost : public browser_sync::ModelSafeWorkerRegistrar {
       DoInitializeOptions(
           const GURL& service_url,
           bool attempt_last_user_authentication,
-          chrome_common_net::NetworkChangeNotifierThread*
-              network_change_notifier_thread,
           sync_api::HttpPostProviderFactory* http_bridge_factory,
           sync_api::HttpPostProviderFactory* auth_http_bridge_factory,
           const std::string& lsid,
@@ -248,7 +237,6 @@ class SyncBackendHost : public browser_sync::ModelSafeWorkerRegistrar {
           NotificationMethod notification_method)
           : service_url(service_url),
             attempt_last_user_authentication(attempt_last_user_authentication),
-            network_change_notifier_thread(network_change_notifier_thread),
             http_bridge_factory(http_bridge_factory),
             auth_http_bridge_factory(auth_http_bridge_factory),
             lsid(lsid),
@@ -259,8 +247,6 @@ class SyncBackendHost : public browser_sync::ModelSafeWorkerRegistrar {
 
       GURL service_url;
       bool attempt_last_user_authentication;
-      chrome_common_net::NetworkChangeNotifierThread*
-          network_change_notifier_thread;
       sync_api::HttpPostProviderFactory* http_bridge_factory;
       sync_api::HttpPostProviderFactory* auth_http_bridge_factory;
       std::string lsid;
@@ -321,19 +307,13 @@ class SyncBackendHost : public browser_sync::ModelSafeWorkerRegistrar {
     // last known user (since it will fail in test mode) and does some extra
     // setup to nudge the syncapi into a useable state.
     void DoInitializeForTest(const std::wstring& test_user,
-                             chrome_common_net::NetworkChangeNotifierThread*
-                                 network_change_notifier_thread,
                              sync_api::HttpPostProviderFactory* factory,
                              sync_api::HttpPostProviderFactory* auth_factory,
                              bool delete_sync_data_folder,
                              NotificationMethod notification_method) {
-      DoInitialize(
-          DoInitializeOptions(GURL(), false,
-                              network_change_notifier_thread,
-                              factory, auth_factory,
-                              std::string(), delete_sync_data_folder,
-                              false, false,
-                              notification_method));
+      DoInitialize(DoInitializeOptions(GURL(), false, factory, auth_factory,
+                                       std::string(), delete_sync_data_folder,
+                                       false, false, notification_method));
         syncapi_->SetupForTestMode(test_user);
     }
 #endif
diff --git a/chrome/browser/sync/net/network_change_notifier_io_thread.cc b/chrome/browser/sync/net/network_change_notifier_io_thread.cc
deleted file mode 100644
index c2cd2b4..0000000
--- a/chrome/browser/sync/net/network_change_notifier_io_thread.cc
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright (c) 2010 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/sync/net/network_change_notifier_io_thread.h"
-
-#include "base/logging.h"
-#include "chrome/browser/io_thread.h"
-
-NetworkChangeNotifierIOThread::NetworkChangeNotifierIOThread(
-    IOThread* io_thread) : io_thread_(io_thread) {
-  DCHECK(io_thread_);
-}
-
-NetworkChangeNotifierIOThread::~NetworkChangeNotifierIOThread() {}
-
-MessageLoop* NetworkChangeNotifierIOThread::GetMessageLoop() const {
-  return io_thread_->message_loop();
-}
-
-net::NetworkChangeNotifier*
-NetworkChangeNotifierIOThread::GetNetworkChangeNotifier() const {
-  return io_thread_->globals()->network_change_notifier.get();
-}
diff --git a/chrome/browser/sync/net/network_change_notifier_io_thread.h b/chrome/browser/sync/net/network_change_notifier_io_thread.h
deleted file mode 100644
index c15156a..0000000
--- a/chrome/browser/sync/net/network_change_notifier_io_thread.h
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright (c) 2010 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.
-
-#ifndef CHROME_BROWSER_SYNC_NET_NETWORK_CHANGE_NOTIFIER_IO_THREAD_H_
-#define CHROME_BROWSER_SYNC_NET_NETWORK_CHANGE_NOTIFIER_IO_THREAD_H_
-
-// This is a simple NetworkChangeNotifierThread wrapper around an
-// IOThread and its NetworkChangeNotifier.
-
-#include "base/basictypes.h"
-#include "chrome/common/net/network_change_notifier_thread.h"
-
-class IOThread;
-class MessageLoop;
-
-class NetworkChangeNotifierIOThread
-    : public chrome_common_net::NetworkChangeNotifierThread {
- public:
-  // Does not take ownership of |io_thread|.  This instance must live
-  // no longer than |io_thread|.
-  explicit NetworkChangeNotifierIOThread(IOThread* io_thread);
-
-  virtual ~NetworkChangeNotifierIOThread();
-
-  // chrome_common_net::NetworkChangeNotifierThread implementation.
-
-  virtual MessageLoop* GetMessageLoop() const;
-
-  virtual net::NetworkChangeNotifier* GetNetworkChangeNotifier() const;
-
- private:
-  IOThread* const io_thread_;
-
-  DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifierIOThread);
-};
-
-#endif  // CHROME_BROWSER_SYNC_NET_NETWORK_CHANGE_NOTIFIER_IO_THREAD_H_
diff --git a/chrome/browser/sync/net/network_change_notifier_io_thread_unittest.cc b/chrome/browser/sync/net/network_change_notifier_io_thread_unittest.cc
deleted file mode 100644
index e2b4e91..0000000
--- a/chrome/browser/sync/net/network_change_notifier_io_thread_unittest.cc
+++ /dev/null
@@ -1,80 +0,0 @@
-// Copyright (c) 2010 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/sync/net/network_change_notifier_io_thread.h"
-
-#include "base/basictypes.h"
-#include "base/message_loop.h"
-#include "base/scoped_ptr.h"
-#include "base/task.h"
-#include "chrome/browser/io_thread.h"
-#include "chrome/common/net/thread_blocker.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace {
-
-class NetworkChangeNotifierIOThreadTest : public testing::Test {
- protected:
-  NetworkChangeNotifierIOThreadTest() {}
-
-  virtual ~NetworkChangeNotifierIOThreadTest() {}
-
-  virtual void SetUp() {
-    // We need to set the message loop type explicitly because
-    // IOThread doesn't do it for us and the Linux
-    // NetworkChangeNotifier expects it.
-    base::Thread::Options options;
-    options.message_loop_type = MessageLoop::TYPE_IO;
-    EXPECT_TRUE(io_thread_.StartWithOptions(options));
-    thread_blocker_.reset(new chrome_common_net::ThreadBlocker(&io_thread_));
-    thread_blocker_->Block();
-    network_change_notifier_io_thread_.reset(
-        new NetworkChangeNotifierIOThread(&io_thread_));
-  }
-
-  virtual void TearDown() {
-    network_change_notifier_io_thread_.reset();
-    // Nothing should be posted on |io_thread_| at this point;
-    // otherwise, it may try to access
-    // network_change_notifier_io_thread_, which now NULL
-    thread_blocker_->Unblock();
-    thread_blocker_.reset();
-    io_thread_.Stop();
-  }
-
-  IOThread io_thread_;
-  scoped_ptr<chrome_common_net::ThreadBlocker> thread_blocker_;
-  scoped_ptr<NetworkChangeNotifierIOThread>
-      network_change_notifier_io_thread_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifierIOThreadTest);
-};
-
-void CompareNetworkChangeNotifiers(
-    IOThread* io_thread,
-    NetworkChangeNotifierIOThread* network_change_notifier_io_thread) {
-  EXPECT_EQ(network_change_notifier_io_thread->GetMessageLoop(),
-            MessageLoop::current());
-  EXPECT_EQ(io_thread->globals()->network_change_notifier.get(),
-            network_change_notifier_io_thread->GetNetworkChangeNotifier());
-}
-
-TEST_F(NetworkChangeNotifierIOThreadTest, Basic) {
-  EXPECT_EQ(io_thread_.message_loop(),
-            network_change_notifier_io_thread_->GetMessageLoop());
-  ASSERT_TRUE(
-      io_thread_.PostTask(ChromeThread::IO,
-                          FROM_HERE,
-                          NewRunnableFunction(
-                              &CompareNetworkChangeNotifiers,
-                              &io_thread_,
-                              network_change_notifier_io_thread_.get())));
-  // Pump the thread to make sure the task we just posted is run
-  // before this test ends.
-  thread_blocker_->Unblock();
-  thread_blocker_->Block();
-}
-
-}  // namespace
diff --git a/chrome/browser/sync/notifier/server_notifier_thread.cc b/chrome/browser/sync/notifier/server_notifier_thread.cc
index fbfc999..093adb4 100644
--- a/chrome/browser/sync/notifier/server_notifier_thread.cc
+++ b/chrome/browser/sync/notifier/server_notifier_thread.cc
@@ -18,10 +18,7 @@
 
 namespace sync_notifier {
 
-ServerNotifierThread::ServerNotifierThread(
-    chrome_common_net::NetworkChangeNotifierThread*
-        network_change_notifier_thread)
-    : notifier::MediatorThreadImpl(network_change_notifier_thread) {}
+ServerNotifierThread::ServerNotifierThread() {}
 
 ServerNotifierThread::~ServerNotifierThread() {}
 
diff --git a/chrome/browser/sync/notifier/server_notifier_thread.h b/chrome/browser/sync/notifier/server_notifier_thread.h
index 9f079e2..021095c 100644
--- a/chrome/browser/sync/notifier/server_notifier_thread.h
+++ b/chrome/browser/sync/notifier/server_notifier_thread.h
@@ -20,10 +20,6 @@
 #include "chrome/common/net/notifier/listener/mediator_thread_impl.h"
 #include "google/cacheinvalidation/invalidation-client.h"
 
-namespace chrome_common_net {
-class NetworkChangeNotifierThread;
-}  // namespace chrome_common_net
-
 namespace sync_notifier {
 
 class ChromeInvalidationClient;
@@ -32,9 +28,7 @@ class ServerNotifierThread
     : public notifier::MediatorThreadImpl,
       public invalidation::InvalidationListener {
  public:
-  explicit ServerNotifierThread(
-      chrome_common_net::NetworkChangeNotifierThread*
-          network_change_notifier_thread);
+  ServerNotifierThread();
 
   virtual ~ServerNotifierThread();
 
diff --git a/chrome/browser/sync/profile_sync_factory_impl.cc b/chrome/browser/sync/profile_sync_factory_impl.cc
index b70d112..1a707ec 100644
--- a/chrome/browser/sync/profile_sync_factory_impl.cc
+++ b/chrome/browser/sync/profile_sync_factory_impl.cc
@@ -61,23 +61,15 @@ using browser_sync::TypedUrlDataTypeController;
 using browser_sync::TypedUrlModelAssociator;
 using browser_sync::UnrecoverableErrorHandler;
 
-ProfileSyncFactoryImpl::ProfileSyncFactoryImpl(
-    Profile* profile,
-    chrome_common_net::NetworkChangeNotifierThread*
-        network_change_notifier_thread,
-    CommandLine* command_line)
+ProfileSyncFactoryImpl::ProfileSyncFactoryImpl(Profile* profile,
+                                               CommandLine* command_line)
     : profile_(profile),
-      network_change_notifier_thread_(network_change_notifier_thread),
       command_line_(command_line) {
-  DCHECK(network_change_notifier_thread_);
 }
 
 ProfileSyncService* ProfileSyncFactoryImpl::CreateProfileSyncService() {
-  ProfileSyncService* pss =
-      new ProfileSyncService(this,
-                             profile_,
-                             network_change_notifier_thread_,
-                             browser_defaults::kBootstrapSyncAuthentication);
+  ProfileSyncService* pss = new ProfileSyncService(
+      this, profile_, browser_defaults::kBootstrapSyncAuthentication);
 
   // Autofill sync is enabled by default.  Register unless explicitly
   // disabled.
diff --git a/chrome/browser/sync/profile_sync_factory_impl.h b/chrome/browser/sync/profile_sync_factory_impl.h
index c26ba4f..31c0dea 100644
--- a/chrome/browser/sync/profile_sync_factory_impl.h
+++ b/chrome/browser/sync/profile_sync_factory_impl.h
@@ -11,17 +11,9 @@
 class CommandLine;
 class Profile;
 
-namespace chrome_common_net {
-class NetworkChangeNotifierThread;
-}
-
 class ProfileSyncFactoryImpl : public ProfileSyncFactory {
  public:
-  ProfileSyncFactoryImpl(
-      Profile* profile,
-      chrome_common_net::NetworkChangeNotifierThread*
-          network_change_notifier_thread,
-      CommandLine* command_line);
+  ProfileSyncFactoryImpl(Profile* profile, CommandLine* command_line);
   virtual ~ProfileSyncFactoryImpl() {}
 
   // ProfileSyncFactory interface.
@@ -65,8 +57,6 @@ class ProfileSyncFactoryImpl : public ProfileSyncFactory {
 
  private:
   Profile* profile_;
-  chrome_common_net::NetworkChangeNotifierThread*
-      network_change_notifier_thread_;
   CommandLine* command_line_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncFactoryImpl);
diff --git a/chrome/browser/sync/profile_sync_factory_impl_unittest.cc b/chrome/browser/sync/profile_sync_factory_impl_unittest.cc
index 0034228..b63c23a 100644
--- a/chrome/browser/sync/profile_sync_factory_impl_unittest.cc
+++ b/chrome/browser/sync/profile_sync_factory_impl_unittest.cc
@@ -13,7 +13,6 @@
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_factory_impl.h"
 #include "chrome/common/chrome_switches.h"
-#include "chrome/common/net/fake_network_change_notifier_thread.h"
 #include "chrome/test/testing_profile.h"
 
 using browser_sync::DataTypeController;
@@ -28,17 +27,13 @@ class ProfileSyncFactoryImplTest : public testing::Test {
     FilePath program_path(FILE_PATH_LITERAL("chrome.exe"));
     command_line_.reset(new CommandLine(program_path));
     profile_sync_service_factory_.reset(
-        new ProfileSyncFactoryImpl(profile_.get(),
-                                   &fake_network_change_notifier_thread_,
-                                   command_line_.get()));
+        new ProfileSyncFactoryImpl(profile_.get(), command_line_.get()));
   }
 
   MessageLoop message_loop_;
   ChromeThread ui_thread_;
   scoped_ptr<Profile> profile_;
   scoped_ptr<CommandLine> command_line_;
-  chrome_common_net::FakeNetworkChangeNotifierThread
-      fake_network_change_notifier_thread_;
   scoped_ptr<ProfileSyncFactoryImpl> profile_sync_service_factory_;
 };
 
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 7b4f3fb..f20c1e3 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -51,16 +51,12 @@ const char* ProfileSyncService::kSyncServerUrl =
 const char* ProfileSyncService::kDevServerUrl =
     "https://clients4.google.com/chrome-sync/dev";
 
-ProfileSyncService::ProfileSyncService(
-    ProfileSyncFactory* factory,
-    Profile* profile,
-    chrome_common_net::NetworkChangeNotifierThread*
-        network_change_notifier_thread,
-    bool bootstrap_sync_authentication)
+ProfileSyncService::ProfileSyncService(ProfileSyncFactory* factory,
+                                       Profile* profile,
+                                       bool bootstrap_sync_authentication)
     : last_auth_error_(AuthError::None()),
       factory_(factory),
       profile_(profile),
-      network_change_notifier_thread_(network_change_notifier_thread),
       bootstrap_sync_authentication_(bootstrap_sync_authentication),
       sync_service_url_(kDevServerUrl),
       backend_initialized_(false),
@@ -72,7 +68,6 @@ ProfileSyncService::ProfileSyncService(
       ALLOW_THIS_IN_INITIALIZER_LIST(scoped_runnable_method_factory_(this)) {
   DCHECK(factory);
   DCHECK(profile);
-  DCHECK(network_change_notifier_thread_);
   registrar_.Add(this,
                  NotificationType::SYNC_CONFIGURE_START,
                  NotificationService::AllSources());
@@ -110,7 +105,6 @@ ProfileSyncService::ProfileSyncService()
     : last_auth_error_(AuthError::None()),
       factory_(NULL),
       profile_(NULL),
-      network_change_notifier_thread_(NULL),
       bootstrap_sync_authentication_(false),
       sync_service_url_(kSyncServerUrl),
       backend_initialized_(false),
@@ -273,7 +267,6 @@ void ProfileSyncService::InitializeBackend(bool delete_sync_data_folder) {
   GetPreferredDataTypes(&types);
   backend_->Initialize(sync_service_url_,
                        types,
-                       network_change_notifier_thread_,
                        profile_->GetRequestContext(),
                        GetLsidForAuthBootstraping(),
                        delete_sync_data_folder,
diff --git a/chrome/browser/sync/profile_sync_service.h b/chrome/browser/sync/profile_sync_service.h
index 929d8bd..b496b12 100644
--- a/chrome/browser/sync/profile_sync_service.h
+++ b/chrome/browser/sync/profile_sync_service.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -31,10 +31,6 @@ class NotificationType;
 class Profile;
 class ProfileSyncFactory;
 
-namespace chrome_common_net {
-class NetworkChangeNotifierThread;
-}
-
 // Various UI components such as the New Tab page can be driven by observing
 // the ProfileSyncService through this interface.
 class ProfileSyncServiceObserver {
@@ -128,8 +124,6 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
 
   ProfileSyncService(ProfileSyncFactory* factory_,
                      Profile* profile,
-                     chrome_common_net::NetworkChangeNotifierThread*
-                         network_change_notifier_thread,
                      bool bootstrap_sync_authentication);
   virtual ~ProfileSyncService();
 
@@ -382,9 +376,6 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
   // The profile whose data we are synchronizing.
   Profile* profile_;
 
-  chrome_common_net::NetworkChangeNotifierThread*
-      network_change_notifier_thread_;
-
   // True if the profile sync service should attempt to use an LSID
   // cookie for authentication.  This is typically set to true in
   // ChromiumOS since we want to use the system level authentication
diff --git a/chrome/browser/sync/sync_setup_wizard_unittest.cc b/chrome/browser/sync/sync_setup_wizard_unittest.cc
index ca63f97..7d2fa769f 100644
--- a/chrome/browser/sync/sync_setup_wizard_unittest.cc
+++ b/chrome/browser/sync/sync_setup_wizard_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -14,7 +14,6 @@
 #include "chrome/browser/sync/profile_sync_factory_mock.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/sync_setup_flow.h"
-#include "chrome/common/net/fake_network_change_notifier_thread.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/browser_with_test_window_test.h"
 #include "chrome/test/testing_profile.h"
@@ -32,9 +31,7 @@ typedef GoogleServiceAuthError AuthError;
 class ProfileSyncServiceForWizardTest : public ProfileSyncService {
  public:
   ProfileSyncServiceForWizardTest(ProfileSyncFactory* factory, Profile* profile)
-      : ProfileSyncService(factory, profile,
-                           &fake_network_change_notifier_thread_,
-                           false),
+      : ProfileSyncService(factory, profile, false),
         user_accepted_merge_and_sync_(false),
         user_cancelled_dialog_(false) {
     RegisterPreferences();
@@ -81,9 +78,6 @@ class ProfileSyncServiceForWizardTest : public ProfileSyncService {
   bool user_cancelled_dialog_;
 
  private:
-  chrome_common_net::FakeNetworkChangeNotifierThread
-      fake_network_change_notifier_thread_;
-
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncServiceForWizardTest);
 };
 
diff --git a/chrome/browser/sync/test_profile_sync_service.h b/chrome/browser/sync/test_profile_sync_service.h
index 6e04d0e..f795998 100644
--- a/chrome/browser/sync/test_profile_sync_service.h
+++ b/chrome/browser/sync/test_profile_sync_service.h
@@ -11,7 +11,6 @@
 #include "chrome/browser/profile.h"
 #include "chrome/browser/sync/profile_sync_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
-#include "chrome/common/net/fake_network_change_notifier_thread.h"
 #include "chrome/test/sync/test_http_bridge_factory.h"
 
 class TestProfileSyncService : public ProfileSyncService {
@@ -20,33 +19,21 @@ class TestProfileSyncService : public ProfileSyncService {
                                   Profile* profile,
                                   bool bootstrap_sync_authentication,
                                   bool synchronous_backend_initialization)
-      : ProfileSyncService(factory, profile,
-                           &fake_network_change_notifier_thread_,
-                           bootstrap_sync_authentication),
+      : ProfileSyncService(factory, profile, bootstrap_sync_authentication),
         synchronous_backend_initialization_(
             synchronous_backend_initialization) {
-    fake_network_change_notifier_thread_.Start();
     RegisterPreferences();
     SetSyncSetupCompleted();
   }
-  virtual ~TestProfileSyncService() {
-    // This needs to happen before
-    // |fake_network_change_notifier_thread_| is stopped.  This is
-    // also called again in ProfileSyncService's destructor, but
-    // calling it multiple times is okay.
-    Shutdown(false);
-    fake_network_change_notifier_thread_.Stop();
-  }
+  virtual ~TestProfileSyncService() { }
 
   virtual void InitializeBackend(bool delete_sync_data_folder) {
     browser_sync::TestHttpBridgeFactory* factory =
         new browser_sync::TestHttpBridgeFactory();
     browser_sync::TestHttpBridgeFactory* factory2 =
         new browser_sync::TestHttpBridgeFactory();
-    backend()->InitializeForTestMode(
-        L"testuser", &fake_network_change_notifier_thread_,
-        factory, factory2, delete_sync_data_folder,
-        browser_sync::kDefaultNotificationMethod);
+    backend()->InitializeForTestMode(L"testuser", factory, factory2,
+        delete_sync_data_folder, browser_sync::kDefaultNotificationMethod);
     // TODO(akalin): Figure out a better way to do this.
     if (synchronous_backend_initialization_) {
       // The SyncBackend posts a task to the current loop when
@@ -74,8 +61,6 @@ class TestProfileSyncService : public ProfileSyncService {
   }
 
   bool synchronous_backend_initialization_;
-  chrome_common_net::FakeNetworkChangeNotifierThread
-      fake_network_change_notifier_thread_;
 };
 
 #endif  // CHROME_BROWSER_SYNC_TEST_PROFILE_SYNC_SERVICE_H_