Merge 253787 "[GCM] Make sure GCM checkout logic is invoked when..."

> [GCM] Make sure GCM checkout logic is invoked when the profile is signed out
> 
> We now always create GCMProfileService that listens to profile
> notifications such that GCM checkout logic could be invoked when the
> profile is signed out.
> 
> We now move the GCM check-in logic from GCMClient::Initialize to GCMClient::CheckIn.
> 
> BUG=344031
> TEST=new tests added and existing tests updated
> 
> Review URL: https://codereview.chromium.org/165993005

TBR=jianli@chromium.org

Review URL: https://codereview.chromium.org/187573007

git-svn-id: svn://svn.chromium.org/chrome/branches/1847/src@255130 0039d316-1c4b-4281-b951-d872f2087c98

19 files changed, 411 insertions, 227 deletions

diff --git a/chrome/browser/extensions/api/gcm/gcm_api.cc b/chrome/browser/extensions/api/gcm/gcm_api.cc
index a8a5be2..ca57f8a 100644
--- a/chrome/browser/extensions/api/gcm/gcm_api.cc
+++ b/chrome/browser/extensions/api/gcm/gcm_api.cc
@@ -97,8 +97,14 @@ bool GcmApiFunction::RunImpl() {
 }
 
 bool GcmApiFunction::IsGcmApiEnabled() const {
-  return gcm::GCMProfileService::IsGCMEnabled(
-             Profile::FromBrowserContext(context()));
+  Profile* profile = Profile::FromBrowserContext(context());
+
+  // GCM is not supported in incognito mode.
+  if (profile->IsOffTheRecord())
+    return false;
+
+  return gcm::GCMProfileService::GetGCMEnabledState(profile) !=
+      gcm::GCMProfileService::ALWAYS_DISABLED;
 }
 
 gcm::GCMProfileService* GcmApiFunction::GCMProfileService() const {
diff --git a/chrome/browser/extensions/api/gcm/gcm_apitest.cc b/chrome/browser/extensions/api/gcm/gcm_apitest.cc
index 41372a1..c463ed9 100644
--- a/chrome/browser/extensions/api/gcm/gcm_apitest.cc
+++ b/chrome/browser/extensions/api/gcm/gcm_apitest.cc
@@ -9,6 +9,7 @@
 #include "chrome/browser/services/gcm/fake_gcm_profile_service.h"
 #include "chrome/browser/services/gcm/gcm_client_factory.h"
 #include "chrome/browser/services/gcm/gcm_profile_service_factory.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/features/feature_channel.h"
 #include "chrome/test/base/ui_test_utils.h"
 
@@ -25,6 +26,7 @@ class GcmApiTest : public ExtensionApiTest {
   GcmApiTest() : fake_gcm_profile_service_(NULL) {}
 
  protected:
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE;
   virtual void SetUpOnMainThread() OVERRIDE;
 
   void StartCollecting();
@@ -38,13 +40,24 @@ class GcmApiTest : public ExtensionApiTest {
   gcm::FakeGCMProfileService* fake_gcm_profile_service_;
 };
 
+void GcmApiTest::SetUpCommandLine(CommandLine* command_line) {
+  // We now always create the GCMProfileService instance in
+  // ProfileSyncServiceFactory that is called when a profile is being
+  // initialized. In order to prevent it from being created, we add the switch
+  // to disable the sync logic.
+  command_line->AppendSwitch(switches::kDisableSync);
+
+  ExtensionApiTest::SetUpCommandLine(command_line);
+}
+
 void GcmApiTest::SetUpOnMainThread() {
   gcm::GCMProfileServiceFactory::GetInstance()->SetTestingFactory(
       browser()->profile(), &gcm::FakeGCMProfileService::Build);
   fake_gcm_profile_service_ = static_cast<gcm::FakeGCMProfileService*>(
       gcm::GCMProfileServiceFactory::GetInstance()->GetForProfile(
           browser()->profile()));
-  gcm::FakeGCMProfileService::EnableGCMForTesting();
+
+  ExtensionApiTest::SetUpOnMainThread();
 }
 
 void GcmApiTest::StartCollecting() {
diff --git a/chrome/browser/services/gcm/fake_gcm_profile_service.cc b/chrome/browser/services/gcm/fake_gcm_profile_service.cc
index dad6bff..c124f4f 100644
--- a/chrome/browser/services/gcm/fake_gcm_profile_service.cc
+++ b/chrome/browser/services/gcm/fake_gcm_profile_service.cc
@@ -19,11 +19,6 @@ BrowserContextKeyedService* FakeGCMProfileService::Build(
   return new FakeGCMProfileService(profile);
 }
 
-// static
-void FakeGCMProfileService::EnableGCMForTesting() {
-  GCMProfileService::enable_gcm_for_testing_ = true;
-}
-
 FakeGCMProfileService::FakeGCMProfileService(Profile* profile)
     : GCMProfileService(profile),
       collect_(false) {}
diff --git a/chrome/browser/services/gcm/fake_gcm_profile_service.h b/chrome/browser/services/gcm/fake_gcm_profile_service.h
index 65757fe..1848c0b 100644
--- a/chrome/browser/services/gcm/fake_gcm_profile_service.h
+++ b/chrome/browser/services/gcm/fake_gcm_profile_service.h
@@ -20,8 +20,6 @@ class FakeGCMProfileService : public GCMProfileService {
   // BrowserContextKeyedService::SetTestingFactory().
   static BrowserContextKeyedService* Build(content::BrowserContext* context);
 
-  static void EnableGCMForTesting();
-
   explicit FakeGCMProfileService(Profile* profile);
   virtual ~FakeGCMProfileService();
 
diff --git a/chrome/browser/services/gcm/gcm_client_mock.cc b/chrome/browser/services/gcm/gcm_client_mock.cc
index 45f4349..e701013 100644
--- a/chrome/browser/services/gcm/gcm_client_mock.cc
+++ b/chrome/browser/services/gcm/gcm_client_mock.cc
@@ -13,10 +13,13 @@
 
 namespace gcm {
 
-GCMClientMock::GCMClientMock(Status status, ErrorSimulation error_simulation)
+GCMClientMock::GCMClientMock(LoadingDelay loading_delay,
+                             ErrorSimulation error_simulation)
     : delegate_(NULL),
-      status_(status),
-      error_simulation_(error_simulation) {
+      status_(UNINITIALIZED),
+      loading_delay_(loading_delay),
+      error_simulation_(error_simulation),
+      weak_ptr_factory_(this) {
 }
 
 GCMClientMock::~GCMClientMock() {
@@ -32,8 +35,26 @@ void GCMClientMock::Initialize(
   delegate_ = delegate;
 }
 
+void GCMClientMock::Load() {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+  DCHECK_NE(LOADED, status_);
+
+  if (loading_delay_ == DELAY_LOADING)
+    return;
+  DoLoading();
+}
+
+void GCMClientMock::DoLoading() {
+  status_ = LOADED;
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&GCMClientMock::CheckinFinished,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
 void GCMClientMock::CheckOut() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+  status_ = CHECKED_OUT;
 }
 
 void GCMClientMock::Register(const std::string& app_id,
@@ -48,7 +69,7 @@ void GCMClientMock::Register(const std::string& app_id,
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&GCMClientMock::RegisterFinished,
-                 base::Unretained(this),
+                 weak_ptr_factory_.GetWeakPtr(),
                  app_id,
                  registration_id));
 }
@@ -64,13 +85,18 @@ void GCMClientMock::Send(const std::string& app_id,
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&GCMClientMock::SendFinished,
-                 base::Unretained(this),
+                 weak_ptr_factory_.GetWeakPtr(),
                  app_id,
                  message.id));
 }
 
-bool GCMClientMock::IsReady() const {
-  return status_ == READY;
+void GCMClientMock::PerformDelayedLoading() {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&GCMClientMock::DoLoading, weak_ptr_factory_.GetWeakPtr()));
 }
 
 void GCMClientMock::ReceiveMessage(const std::string& app_id,
@@ -81,7 +107,7 @@ void GCMClientMock::ReceiveMessage(const std::string& app_id,
       content::BrowserThread::IO,
       FROM_HERE,
       base::Bind(&GCMClientMock::MessageReceived,
-                 base::Unretained(this),
+                 weak_ptr_factory_.GetWeakPtr(),
                  app_id,
                  message));
 }
@@ -93,22 +119,10 @@ void GCMClientMock::DeleteMessages(const std::string& app_id) {
       content::BrowserThread::IO,
       FROM_HERE,
       base::Bind(&GCMClientMock::MessagesDeleted,
-                 base::Unretained(this),
+                 weak_ptr_factory_.GetWeakPtr(),
                  app_id));
 }
 
-void GCMClientMock::SetReady() {
-  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  DCHECK_EQ(status_, NOT_READY);
-
-  status_ = READY;
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(&GCMClientMock::SetReadyOnIO,
-                 base::Unretained(this)));
-}
-
 // static
 std::string GCMClientMock::GetRegistrationIdFromSenderIds(
     const std::vector<std::string>& sender_ids) {
@@ -131,6 +145,10 @@ std::string GCMClientMock::GetRegistrationIdFromSenderIds(
   return registration_id;
 }
 
+void GCMClientMock::CheckinFinished() {
+  delegate_->OnGCMReady();
+}
+
 void GCMClientMock::RegisterFinished(const std::string& app_id,
                                      const std::string& registrion_id) {
   delegate_->OnRegisterFinished(
@@ -146,7 +164,7 @@ void GCMClientMock::SendFinished(const std::string& app_id,
     base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&GCMClientMock::MessageSendError,
-                   base::Unretained(this),
+                   weak_ptr_factory_.GetWeakPtr(),
                    app_id,
                    message_id),
         base::TimeDelta::FromMilliseconds(200));
@@ -170,8 +188,4 @@ void GCMClientMock::MessageSendError(const std::string& app_id,
     delegate_->OnMessageSendError(app_id, message_id, NETWORK_ERROR);
 }
 
-void GCMClientMock::SetReadyOnIO() {
-  delegate_->OnGCMReady();
-}
-
 }  // namespace gcm
diff --git a/chrome/browser/services/gcm/gcm_client_mock.h b/chrome/browser/services/gcm/gcm_client_mock.h
index 485a6a8..a10b483 100644
--- a/chrome/browser/services/gcm/gcm_client_mock.h
+++ b/chrome/browser/services/gcm/gcm_client_mock.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_SERVICES_GCM_GCM_CLIENT_MOCK_H_
 
 #include "base/compiler_specific.h"
+#include "base/memory/weak_ptr.h"
 #include "google_apis/gcm/gcm_client.h"
 
 namespace gcm {
@@ -13,8 +14,14 @@ namespace gcm {
 class GCMClientMock : public GCMClient {
  public:
   enum Status {
-    NOT_READY,
-    READY
+    UNINITIALIZED,
+    LOADED,
+    CHECKED_OUT
+  };
+
+  enum LoadingDelay {
+    NO_DELAY_LOADING,
+    DELAY_LOADING,
   };
 
   enum ErrorSimulation {
@@ -22,9 +29,9 @@ class GCMClientMock : public GCMClient {
     FORCE_ERROR
   };
 
-  // |status| denotes if the fake client is ready or not at the beginning.
+  // |loading_delay| denotes if the check-in should be delayed.
   // |error_simulation| denotes if we should simulate server error.
-  GCMClientMock(Status status, ErrorSimulation error_simulation);
+  GCMClientMock(LoadingDelay loading_delay, ErrorSimulation error_simulation);
   virtual ~GCMClientMock();
 
   // Overridden from GCMClient:
@@ -36,6 +43,7 @@ class GCMClientMock : public GCMClient {
       const scoped_refptr<net::URLRequestContextGetter>&
           url_request_context_getter,
       Delegate* delegate) OVERRIDE;
+  virtual void Load() OVERRIDE;
   virtual void CheckOut() OVERRIDE;
   virtual void Register(const std::string& app_id,
                         const std::string& cert,
@@ -44,7 +52,10 @@ class GCMClientMock : public GCMClient {
   virtual void Send(const std::string& app_id,
                     const std::string& receiver_id,
                     const OutgoingMessage& message) OVERRIDE;
-  virtual bool IsReady() const OVERRIDE;
+
+  // Initiate the loading that has been delayed.
+  // Called on UI thread.
+  void PerformDelayedLoading();
 
   // Simulate receiving something from the server.
   // Called on UI thread.
@@ -52,14 +63,15 @@ class GCMClientMock : public GCMClient {
                       const IncomingMessage& message);
   void DeleteMessages(const std::string& app_id);
 
-  // Can only transition from non-ready to ready.
-  void SetReady();
-
   static std::string GetRegistrationIdFromSenderIds(
       const std::vector<std::string>& sender_ids);
 
+  Status status() const { return status_; }
+
  private:
   // Called on IO thread.
+  void DoLoading();
+  void CheckinFinished();
   void RegisterFinished(const std::string& app_id,
                         const std::string& registrion_id);
   void SendFinished(const std::string& app_id, const std::string& message_id);
@@ -68,11 +80,12 @@ class GCMClientMock : public GCMClient {
   void MessagesDeleted(const std::string& app_id);
   void MessageSendError(const std::string& app_id,
                         const std::string& message_id);
-  void SetReadyOnIO();
 
   Delegate* delegate_;
   Status status_;
+  LoadingDelay loading_delay_;
   ErrorSimulation error_simulation_;
+  base::WeakPtrFactory<GCMClientMock> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GCMClientMock);
 };
diff --git a/chrome/browser/services/gcm/gcm_profile_service.cc b/chrome/browser/services/gcm/gcm_profile_service.cc
index b58f7e6..8bb4627 100644
--- a/chrome/browser/services/gcm/gcm_profile_service.cc
+++ b/chrome/browser/services/gcm/gcm_profile_service.cc
@@ -232,7 +232,7 @@ class GCMProfileService::IOWorker
       public base::RefCountedThreadSafe<GCMProfileService::IOWorker>{
  public:
   // Called on UI thread.
-  explicit IOWorker(const base::WeakPtr<GCMProfileService>& service);
+  IOWorker();
 
   // Overridden from GCMClient::Delegate:
   // Called on IO thread.
@@ -255,11 +255,12 @@ class GCMProfileService::IOWorker
 
   // Called on IO thread.
   void Initialize(
-      GCMClientFactory* gcm_client_factory,
+      scoped_ptr<GCMClientFactory> gcm_client_factory,
       const base::FilePath& store_path,
       const scoped_refptr<net::URLRequestContextGetter>&
           url_request_context_getter);
   void Reset();
+  void Load(const base::WeakPtr<GCMProfileService>& service);
   void CheckOut();
   void Register(const std::string& app_id,
                 const std::vector<std::string>& sender_ids,
@@ -269,18 +270,19 @@ class GCMProfileService::IOWorker
             const std::string& receiver_id,
             const GCMClient::OutgoingMessage& message);
 
+  // For testing purpose. Can be called from UI thread. Use with care.
+  GCMClient* gcm_client_for_testing() const { return gcm_client_.get(); }
+
  private:
   friend class base::RefCountedThreadSafe<IOWorker>;
   virtual ~IOWorker();
 
-  const base::WeakPtr<GCMProfileService> service_;
+  base::WeakPtr<GCMProfileService> service_;
 
   scoped_ptr<GCMClient> gcm_client_;
 };
 
-GCMProfileService::IOWorker::IOWorker(
-    const base::WeakPtr<GCMProfileService>& service)
-    : service_(service) {
+GCMProfileService::IOWorker::IOWorker() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 }
 
@@ -288,7 +290,7 @@ GCMProfileService::IOWorker::~IOWorker() {
 }
 
 void GCMProfileService::IOWorker::Initialize(
-    GCMClientFactory* gcm_client_factory,
+    scoped_ptr<GCMClientFactory> gcm_client_factory,
     const base::FilePath& store_path,
     const scoped_refptr<net::URLRequestContextGetter>&
         url_request_context_getter) {
@@ -313,13 +315,6 @@ void GCMProfileService::IOWorker::Initialize(
                           blocking_task_runner,
                           url_request_context_getter,
                           this);
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::UI,
-      FROM_HERE,
-      base::Bind(&GCMProfileService::FinishInitializationOnUI,
-                 service_,
-                 gcm_client_->IsReady()));
 }
 
 void GCMProfileService::IOWorker::Reset() {
@@ -417,11 +412,21 @@ void GCMProfileService::IOWorker::OnGCMReady() {
                  service_));
 }
 
+void GCMProfileService::IOWorker::Load(
+    const base::WeakPtr<GCMProfileService>& service) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+
+  service_ = service;
+  gcm_client_->Load();
+}
+
 void GCMProfileService::IOWorker::CheckOut() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
 
   gcm_client_->CheckOut();
-  gcm_client_.reset();
+
+  // Note that we still need to keep GCMClient instance alive since the profile
+  // might be signed in again.
 }
 
 void GCMProfileService::IOWorker::Register(
@@ -458,18 +463,19 @@ bool GCMProfileService::RegistrationInfo::IsValid() const {
   return !sender_ids.empty() && !registration_id.empty();
 }
 
-bool GCMProfileService::enable_gcm_for_testing_ = false;
-
 // static
-bool GCMProfileService::IsGCMEnabled(Profile* profile) {
-  // GCM is not enabled in incognito mode.
-  if (profile->IsOffTheRecord())
-    return false;
+GCMProfileService::GCMEnabledState GCMProfileService::GetGCMEnabledState(
+    Profile* profile) {
+  const base::Value* gcm_enabled_value =
+      profile->GetPrefs()->GetUserPrefValue(prefs::kGCMChannelEnabled);
+  if (!gcm_enabled_value)
+    return ENABLED_FOR_APPS;
 
-  if (enable_gcm_for_testing_)
-    return true;
+  bool gcm_enabled = false;
+  if (!gcm_enabled_value->GetAsBoolean(&gcm_enabled))
+    return ENABLED_FOR_APPS;
 
-  return profile->GetPrefs()->GetBoolean(prefs::kGCMChannelEnabled);
+  return gcm_enabled ? ALWAYS_ENABLED : ALWAYS_DISABLED;
 }
 
 // static
@@ -505,15 +511,6 @@ GCMProfileService::~GCMProfileService() {
 
 void GCMProfileService::Initialize(
     scoped_ptr<GCMClientFactory> gcm_client_factory) {
-  gcm_client_factory_ = gcm_client_factory.Pass();
-
-  // This has to be done first since CheckIn depends on it.
-  io_worker_ = new IOWorker(weak_ptr_factory_.GetWeakPtr());
-
-#if !defined(OS_ANDROID)
-  js_event_router_.reset(new extensions::GcmJsEventRouter(profile_));
-#endif
-
   registrar_.Add(this,
                  chrome::NOTIFICATION_GOOGLE_SIGNIN_SUCCESSFUL,
                  content::Source<Profile>(profile_));
@@ -528,14 +525,24 @@ void GCMProfileService::Initialize(
                  chrome:: NOTIFICATION_EXTENSION_UNINSTALLED,
                  content::Source<Profile>(profile_));
 
-  // In case that the profile has been signed in before GCMProfileService is
-  // created.
-  SigninManagerBase* manager = SigninManagerFactory::GetForProfile(profile_);
-  if (manager) {
-    std::string username = manager->GetAuthenticatedUsername();
-    if (!username.empty())
-      CheckIn(username);
-  }
+  // Create and initialize the GCMClient. Note that this does not initiate the
+  // GCM check-in.
+  io_worker_ = new IOWorker();
+  scoped_refptr<net::URLRequestContextGetter> url_request_context_getter =
+      profile_->GetRequestContext();
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&GCMProfileService::IOWorker::Initialize,
+                 io_worker_,
+                 base::Passed(&gcm_client_factory),
+                 profile_->GetPath().Append(chrome::kGCMStoreDirname),
+                 url_request_context_getter));
+
+  // Load from the GCM store and initiate the GCM check-in if the rollout signal
+  // indicates yes.
+  if (GetGCMEnabledState(profile_) == ALWAYS_ENABLED)
+    EnsureLoaded();
 }
 
 void GCMProfileService::Register(const std::string& app_id,
@@ -545,6 +552,9 @@ void GCMProfileService::Register(const std::string& app_id,
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(!app_id.empty() && !sender_ids.empty() && !callback.is_null());
 
+  // Ensure that check-in has been done.
+  EnsureLoaded();
+
   // If the profile was not signed in, bail out.
   if (username_.empty()) {
     callback.Run(std::string(), GCMClient::NOT_SIGNED_IN);
@@ -630,6 +640,9 @@ void GCMProfileService::Send(const std::string& app_id,
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(!app_id.empty() && !receiver_id.empty() && !callback.is_null());
 
+  // Ensure that check-in has been done.
+  EnsureLoaded();
+
   // If the profile was not signed in, bail out.
   if (username_.empty()) {
     callback.Run(std::string(), GCMClient::NOT_SIGNED_IN);
@@ -674,6 +687,10 @@ void GCMProfileService::DoSend(const std::string& app_id,
                  message));
 }
 
+GCMClient* GCMProfileService::GetGCMClientForTesting() const {
+  return io_worker_ ? io_worker_->gcm_client_for_testing() : NULL;
+}
+
 void GCMProfileService::Observe(int type,
                                 const content::NotificationSource& source,
                                 const content::NotificationDetails& details) {
@@ -681,11 +698,8 @@ void GCMProfileService::Observe(int type,
 
   switch (type) {
     case chrome::NOTIFICATION_GOOGLE_SIGNIN_SUCCESSFUL: {
-      const GoogleServiceSigninSuccessDetails* signin_details =
-          content::Details<GoogleServiceSigninSuccessDetails>(details).ptr();
-      // This could be called multiple times when the password changed.
-      if (username_ != signin_details->username)
-        CheckIn(signin_details->username);
+      if (GetGCMEnabledState(profile_) == ALWAYS_ENABLED)
+        EnsureLoaded();
       break;
     }
     case chrome::NOTIFICATION_GOOGLE_SIGNED_OUT:
@@ -694,46 +708,68 @@ void GCMProfileService::Observe(int type,
     case chrome::NOTIFICATION_PROFILE_DESTROYED:
       ResetGCMClient();
       break;
-    case chrome:: NOTIFICATION_EXTENSION_UNINSTALLED: {
-      extensions::Extension* extension =
-          content::Details<extensions::Extension>(details).ptr();
-      Unregister(extension->id());
+    case chrome:: NOTIFICATION_EXTENSION_UNINSTALLED:
+      if (!username_.empty()) {
+        extensions::Extension* extension =
+            content::Details<extensions::Extension>(details).ptr();
+        Unregister(extension->id());
+      }
       break;
-    }
     default:
       NOTREACHED();
   }
 }
 
-void GCMProfileService::CheckIn(const std::string& username) {
-  DCHECK(!username.empty() && username_.empty());
+void GCMProfileService::EnsureLoaded() {
+  SigninManagerBase* manager = SigninManagerFactory::GetForProfile(profile_);
+  if (!manager)
+    return;
+  std::string username = manager->GetAuthenticatedUsername();
+  if (username.empty())
+    return;
+
+  // CheckIn could be called more than once when:
+  // 1) The password changes.
+  // 2) Register/send function calls it to ensure CheckIn is done.
+  if (username_ == username)
+    return;
   username_ = username;
 
+#if !defined(OS_ANDROID)
+  if (!js_event_router_)
+    js_event_router_.reset(new extensions::GcmJsEventRouter(profile_));
+#endif
+
   DCHECK(!delayed_task_controller_);
   delayed_task_controller_.reset(new DelayedTaskController);
 
-  // Load all register apps.
+  // Load all the registered apps.
   ReadRegisteredAppIDs();
 
-  // Let the IO thread create and initialize GCMClient.
-  scoped_refptr<net::URLRequestContextGetter> url_request_context_getter =
-      profile_->GetRequestContext();
+  // This will load the data from the gcm store and trigger the check-in if
+  // the persisted check-in info is not found.
+  // Note that we need to pass weak pointer again since the existing weak
+  // pointer in IOWorker might have been invalidated when check-out occurs.
   content::BrowserThread::PostTask(
       content::BrowserThread::IO,
       FROM_HERE,
-      base::Bind(&GCMProfileService::IOWorker::Initialize,
+      base::Bind(&GCMProfileService::IOWorker::Load,
                  io_worker_,
-                 gcm_client_factory_.get(),
-                 profile_->GetPath().Append(chrome::kGCMStoreDirname),
-                 url_request_context_getter));
+                 weak_ptr_factory_.GetWeakPtr()));
 }
 
 void GCMProfileService::CheckOut() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
-  DCHECK(!username_.empty());
+  // We still proceed with the check-out logic even if the check-in is not
+  // initiated in the current session. This will make sure that all the
+  // persisted data written previously will get purged.
   username_.clear();
 
+  // Remove all the queued tasks since they no longer make sense after
+  // check-out.
+  weak_ptr_factory_.InvalidateWeakPtrs();
+
   // Remove persisted data from app's state store.
   for (RegistrationInfoMap::const_iterator iter =
            registration_info_map_.begin();
@@ -742,7 +778,6 @@ void GCMProfileService::CheckOut() {
   }
 
   // Remove persisted data from prefs store.
-  profile_->GetPrefs()->ClearPref(prefs::kGCMChannelEnabled);
   profile_->GetPrefs()->ClearPref(prefs::kGCMRegisteredAppIDs);
 
   gcm_client_ready_ = false;
@@ -888,14 +923,6 @@ void GCMProfileService::MessageSendError(const std::string& app_id,
   GetEventRouter(app_id)->OnSendError(app_id, message_id, result);
 }
 
-void GCMProfileService::FinishInitializationOnUI(bool ready) {
-  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-
-  gcm_client_ready_ = ready;
-  if (gcm_client_ready_)
-    delayed_task_controller_->SetGCMReady();
-}
-
 void GCMProfileService::GCMClientReady() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
diff --git a/chrome/browser/services/gcm/gcm_profile_service.h b/chrome/browser/services/gcm/gcm_profile_service.h
index 633a6e8c..a516d71 100644
--- a/chrome/browser/services/gcm/gcm_profile_service.h
+++ b/chrome/browser/services/gcm/gcm_profile_service.h
@@ -47,14 +47,24 @@ class GCMProfileService : public BrowserContextKeyedService,
   typedef base::Callback<void(const std::string& message_id,
                               GCMClient::Result result)> SendCallback;
 
+  enum GCMEnabledState {
+    // GCM is always enabled. GCMClient will always load and connect with GCM.
+    ALWAYS_ENABLED,
+    // GCM is only enabled for apps. GCMClient will start to load and connect
+    // with GCM only when GCM API is used.
+    ENABLED_FOR_APPS,
+    // GCM is always disabled. GCMClient will never load and connect with GCM.
+    ALWAYS_DISABLED
+  };
+
   // For testing purpose.
   class TestingDelegate {
    public:
     virtual GCMEventRouter* GetEventRouter() const = 0;
   };
 
-  // Returns true if the GCM support is enabled.
-  static bool IsGCMEnabled(Profile* profile);
+  // Returns the GCM enabled state.
+  static GCMEnabledState GetGCMEnabledState(Profile* profile);
 
   // Register profile-specific prefs for GCM.
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
@@ -88,15 +98,12 @@ class GCMProfileService : public BrowserContextKeyedService,
                     SendCallback callback);
 
   // For testing purpose.
+  GCMClient* GetGCMClientForTesting() const;
+
   void set_testing_delegate(TestingDelegate* testing_delegate) {
     testing_delegate_ = testing_delegate;
   }
 
- protected:
-  // Flag that could be set by the testing code to enable GCM. Otherwise,
-  // tests from official build will fail.
-  static bool enable_gcm_for_testing_;
-
  private:
   friend class GCMProfileServiceTestConsumer;
 
@@ -117,9 +124,9 @@ class GCMProfileService : public BrowserContextKeyedService,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
-  // Checks in with GCM by creating and initializing GCMClient when the profile
-  // has been signed in.
-  void CheckIn(const std::string& username);
+  // Ensures that the GCMClient is loaded and the GCM check-in is done when
+  // the profile was signed in.
+  void EnsureLoaded();
 
   // Checks out of GCM when the profile has been signed out. This will erase
   // all the cached and persisted data.
@@ -155,7 +162,6 @@ class GCMProfileService : public BrowserContextKeyedService,
   void MessageSendError(const std::string& app_id,
                         const std::string& message_id,
                         GCMClient::Result result);
-  void FinishInitializationOnUI(bool ready);
   void GCMClientReady();
 
   // Returns the event router to fire the event for the given app.
@@ -181,9 +187,6 @@ class GCMProfileService : public BrowserContextKeyedService,
   // The profile which owns this object.
   Profile* profile_;
 
-  // Used to creat the GCMClient instance.
-  scoped_ptr<GCMClientFactory> gcm_client_factory_;
-
   // Flag to indicate if GCMClient is ready.
   bool gcm_client_ready_;
 
diff --git a/chrome/browser/services/gcm/gcm_profile_service_factory.cc b/chrome/browser/services/gcm/gcm_profile_service_factory.cc
index aff75d8..c5b2469 100644
--- a/chrome/browser/services/gcm/gcm_profile_service_factory.cc
+++ b/chrome/browser/services/gcm/gcm_profile_service_factory.cc
@@ -14,7 +14,8 @@ namespace gcm {
 
 // static
 GCMProfileService* GCMProfileServiceFactory::GetForProfile(Profile* profile) {
-  if (!gcm::GCMProfileService::IsGCMEnabled(profile))
+  // GCM is not supported in incognito mode.
+  if (profile->IsOffTheRecord())
     return NULL;
 
   return static_cast<GCMProfileService*>(
@@ -38,8 +39,6 @@ GCMProfileServiceFactory::~GCMProfileServiceFactory() {
 BrowserContextKeyedService* GCMProfileServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = static_cast<Profile*>(context);
-  if (!gcm::GCMProfileService::IsGCMEnabled(profile))
-    return NULL;
   GCMProfileService* service = new GCMProfileService(profile);
   scoped_ptr<GCMClientFactory> gcm_client_factory(new GCMClientFactory);
   service->Initialize(gcm_client_factory.Pass());
diff --git a/chrome/browser/services/gcm/gcm_profile_service_unittest.cc b/chrome/browser/services/gcm/gcm_profile_service_unittest.cc
index 395fa14..99a8281 100644
--- a/chrome/browser/services/gcm/gcm_profile_service_unittest.cc
+++ b/chrome/browser/services/gcm/gcm_profile_service_unittest.cc
@@ -98,7 +98,14 @@ class Waiter {
   void OnIOLoopPump() {
     DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
 
-    base::MessageLoop::current()->RunUntilIdle();
+    content::BrowserThread::PostTask(
+        content::BrowserThread::IO,
+        FROM_HERE,
+        base::Bind(&Waiter::OnIOLoopPumpCompleted, base::Unretained(this)));
+  }
+
+  void OnIOLoopPumpCompleted() {
+    DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
 
     content::BrowserThread::PostTask(
         content::BrowserThread::UI,
@@ -214,9 +221,9 @@ class FakeGCMEventRouter : public GCMEventRouter {
 class FakeGCMClientFactory : public GCMClientFactory {
  public:
   FakeGCMClientFactory(
-      GCMClientMock::Status gcm_client_initial_status,
+      GCMClientMock::LoadingDelay gcm_client_loading_delay,
       GCMClientMock::ErrorSimulation gcm_client_error_simulation)
-      : gcm_client_initial_status_(gcm_client_initial_status),
+      : gcm_client_loading_delay_(gcm_client_loading_delay),
         gcm_client_error_simulation_(gcm_client_error_simulation),
         gcm_client_(NULL) {
   }
@@ -225,7 +232,7 @@ class FakeGCMClientFactory : public GCMClientFactory {
   }
 
   virtual scoped_ptr<GCMClient> BuildInstance() OVERRIDE {
-    gcm_client_ = new GCMClientMock(gcm_client_initial_status_,
+    gcm_client_ = new GCMClientMock(gcm_client_loading_delay_,
                                     gcm_client_error_simulation_);
     return scoped_ptr<GCMClient>(gcm_client_);
   }
@@ -233,7 +240,7 @@ class FakeGCMClientFactory : public GCMClientFactory {
   GCMClientMock* gcm_client() const { return gcm_client_; }
 
  private:
-  GCMClientMock::Status gcm_client_initial_status_;
+  GCMClientMock::LoadingDelay gcm_client_loading_delay_;
   GCMClientMock::ErrorSimulation gcm_client_error_simulation_;
   GCMClientMock* gcm_client_;
 
@@ -256,7 +263,7 @@ class GCMProfileServiceTestConsumer : public GCMProfileService::TestingDelegate{
       : waiter_(waiter),
         extension_service_(NULL),
         signin_manager_(NULL),
-        gcm_client_initial_status_(GCMClientMock::READY),
+        gcm_client_loading_delay_(GCMClientMock::NO_DELAY_LOADING),
         gcm_client_error_simulation_(GCMClientMock::ALWAYS_SUCCEED),
         registration_result_(GCMClient::SUCCESS),
         has_persisted_registration_info_(false),
@@ -278,7 +285,7 @@ class GCMProfileServiceTestConsumer : public GCMProfileService::TestingDelegate{
     extension_service_ = extension_system->Get(profile())->extension_service();
 
     // Enable GCM such that tests could be run on all channels.
-    GCMProfileService::enable_gcm_for_testing_ = true;
+    profile()->GetPrefs()->SetBoolean(prefs::kGCMChannelEnabled, true);
 
     // Mock a GCMEventRouter.
     gcm_event_router_.reset(new FakeGCMEventRouter(waiter_));
@@ -334,7 +341,7 @@ class GCMProfileServiceTestConsumer : public GCMProfileService::TestingDelegate{
             profile(), &GCMProfileServiceTestConsumer::BuildGCMProfileService));
     gcm_profile_service->set_testing_delegate(this);
     scoped_ptr<GCMClientFactory> gcm_client_factory(
-        new FakeGCMClientFactory(gcm_client_initial_status_,
+        new FakeGCMClientFactory(gcm_client_loading_delay_,
                                  gcm_client_error_simulation_));
     gcm_profile_service->Initialize(gcm_client_factory.Pass());
     waiter_->PumpIOLoop();
@@ -411,8 +418,8 @@ class GCMProfileServiceTestConsumer : public GCMProfileService::TestingDelegate{
   }
 
   GCMClientMock* GetGCMClient() const {
-    return static_cast<FakeGCMClientFactory*>(
-        GetGCMProfileService()->gcm_client_factory_.get())->gcm_client();
+    return static_cast<GCMClientMock*>(
+        GetGCMProfileService()->GetGCMClientForTesting());
   }
 
   const std::string& GetUsername() const {
@@ -432,8 +439,8 @@ class GCMProfileServiceTestConsumer : public GCMProfileService::TestingDelegate{
     return gcm_event_router_.get();
   }
 
-  void set_gcm_client_initial_status(GCMClientMock::Status status) {
-    gcm_client_initial_status_ = status;
+  void set_gcm_client_loading_delay(GCMClientMock::LoadingDelay delay) {
+    gcm_client_loading_delay_ = delay;
   }
   void set_gcm_client_error_simulation(GCMClientMock::ErrorSimulation error) {
     gcm_client_error_simulation_ = error;
@@ -465,7 +472,7 @@ class GCMProfileServiceTestConsumer : public GCMProfileService::TestingDelegate{
   FakeSigninManager* signin_manager_;  // Not owned.
   scoped_ptr<FakeGCMEventRouter> gcm_event_router_;
 
-  GCMClientMock::Status gcm_client_initial_status_;
+  GCMClientMock::LoadingDelay gcm_client_loading_delay_;
   GCMClientMock::ErrorSimulation gcm_client_error_simulation_;
 
   std::string registration_id_;
@@ -584,7 +591,67 @@ TEST_F(GCMProfileServiceTest, CreateGCMProfileServiceAfterProfileSignIn) {
   EXPECT_FALSE(consumer()->GetUsername().empty());
 }
 
-TEST_F(GCMProfileServiceTest, RegsiterWhenNotSignedIn) {
+TEST_F(GCMProfileServiceTest, SignInAndSignOutUnderPositiveChannelSignal) {
+  // Positive channel signal is provided in SetUp.
+  consumer()->CreateGCMProfileServiceInstance();
+  consumer()->SignIn(kTestingUsername);
+
+  // GCMClient should be loaded.
+  EXPECT_TRUE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::LOADED, consumer()->GetGCMClient()->status());
+
+  consumer()->SignOut();
+
+  // GCMClient should be checked out.
+  EXPECT_FALSE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::CHECKED_OUT, consumer()->GetGCMClient()->status());
+}
+
+TEST_F(GCMProfileServiceTest, SignInAndSignOutUnderNegativeChannelSignal) {
+  // Negative channel signal will prevent GCMClient from checking in when the
+  // profile is signed in.
+  profile()->GetPrefs()->SetBoolean(prefs::kGCMChannelEnabled, false);
+
+  consumer()->CreateGCMProfileServiceInstance();
+  consumer()->SignIn(kTestingUsername);
+
+  // GCMClient should not be loaded.
+  EXPECT_FALSE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::UNINITIALIZED, consumer()->GetGCMClient()->status());
+
+  consumer()->SignOut();
+
+  // Check-out should still be performed.
+  EXPECT_FALSE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::CHECKED_OUT, consumer()->GetGCMClient()->status());
+}
+
+TEST_F(GCMProfileServiceTest, SignOutAndThenSignIn) {
+  // Positive channel signal is provided in SetUp.
+  consumer()->CreateGCMProfileServiceInstance();
+  consumer()->SignIn(kTestingUsername);
+
+  // GCMClient should be loaded.
+  EXPECT_TRUE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::LOADED, consumer()->GetGCMClient()->status());
+
+  consumer()->SignOut();
+
+  // GCMClient should be checked out.
+  EXPECT_FALSE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::CHECKED_OUT, consumer()->GetGCMClient()->status());
+
+  // Sign-in with a different username.
+  consumer()->SignIn(kTestingUsername2);
+
+  // GCMClient should be loaded again.
+  EXPECT_TRUE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::LOADED, consumer()->GetGCMClient()->status());
+}
+
+TEST_F(GCMProfileServiceTest, RegisterWhenNotSignedIn) {
+  consumer()->CreateGCMProfileServiceInstance();
+
   std::vector<std::string> sender_ids;
   sender_ids.push_back("sender1");
   consumer()->Register(kTestingAppId, sender_ids);
@@ -593,7 +660,38 @@ TEST_F(GCMProfileServiceTest, RegsiterWhenNotSignedIn) {
   EXPECT_EQ(GCMClient::NOT_SIGNED_IN, consumer()->registration_result());
 }
 
+TEST_F(GCMProfileServiceTest, RegisterUnderNeutralChannelSignal) {
+  // Neutral channel signal will prevent GCMClient from checking in when the
+  // profile is signed in.
+  profile()->GetPrefs()->ClearPref(prefs::kGCMChannelEnabled);
+
+  consumer()->CreateGCMProfileServiceInstance();
+  consumer()->SignIn(kTestingUsername);
+
+  // GCMClient should not be checked in.
+  EXPECT_FALSE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::UNINITIALIZED, consumer()->GetGCMClient()->status());
+
+  // Invoking register will make GCMClient checked in.
+  std::vector<std::string> sender_ids;
+  sender_ids.push_back("sender1");
+  consumer()->Register(kTestingAppId, sender_ids);
+  WaitUntilCompleted();
+
+  // GCMClient should be checked in.
+  EXPECT_TRUE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::LOADED, consumer()->GetGCMClient()->status());
+
+  // Registration should succeed.
+  std::string expected_registration_id =
+      GCMClientMock::GetRegistrationIdFromSenderIds(sender_ids);
+  EXPECT_EQ(expected_registration_id, consumer()->registration_id());
+  EXPECT_EQ(GCMClient::SUCCESS, consumer()->registration_result());
+}
+
 TEST_F(GCMProfileServiceTest, SendWhenNotSignedIn) {
+  consumer()->CreateGCMProfileServiceInstance();
+
   GCMClient::OutgoingMessage message;
   message.id = "1";
   message.data["key1"] = "value1";
@@ -603,6 +701,34 @@ TEST_F(GCMProfileServiceTest, SendWhenNotSignedIn) {
   EXPECT_EQ(GCMClient::NOT_SIGNED_IN, consumer()->send_result());
 }
 
+TEST_F(GCMProfileServiceTest, SendUnderNeutralChannelSignal) {
+  // Neutral channel signal will prevent GCMClient from checking in when the
+  // profile is signed in.
+  profile()->GetPrefs()->ClearPref(prefs::kGCMChannelEnabled);
+
+  consumer()->CreateGCMProfileServiceInstance();
+  consumer()->SignIn(kTestingUsername);
+
+  // GCMClient should not be checked in.
+  EXPECT_FALSE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::UNINITIALIZED, consumer()->GetGCMClient()->status());
+
+  // Invoking send will make GCMClient checked in.
+  GCMClient::OutgoingMessage message;
+  message.id = "1";
+  message.data["key1"] = "value1";
+  consumer()->Send(kTestingAppId, kUserId, message);
+  WaitUntilCompleted();
+
+  // GCMClient should be checked in.
+  EXPECT_TRUE(consumer()->IsGCMClientReady());
+  EXPECT_EQ(GCMClientMock::LOADED, consumer()->GetGCMClient()->status());
+
+  // Sending should succeed.
+  EXPECT_EQ(consumer()->send_message_id(), message.id);
+  EXPECT_EQ(GCMClient::SUCCESS, consumer()->send_result());
+}
+
 // Tests single-profile.
 class GCMProfileServiceSingleProfileTest : public GCMProfileServiceTest {
  public:
@@ -620,29 +746,6 @@ class GCMProfileServiceSingleProfileTest : public GCMProfileServiceTest {
   }
 };
 
-TEST_F(GCMProfileServiceSingleProfileTest, SignOut) {
-  EXPECT_TRUE(consumer()->IsGCMClientReady());
-
-  // This will trigger check-out.
-  consumer()->SignOut();
-
-  EXPECT_FALSE(consumer()->IsGCMClientReady());
-}
-
-TEST_F(GCMProfileServiceSingleProfileTest, SignOutAndThenSignIn) {
-  EXPECT_TRUE(consumer()->IsGCMClientReady());
-
-  // This will trigger check-out.
-  consumer()->SignOut();
-
-  EXPECT_FALSE(consumer()->IsGCMClientReady());
-
-  // Sign-in with a different username.
-  consumer()->SignIn(kTestingUsername2);
-
-  EXPECT_TRUE(consumer()->IsGCMClientReady());
-}
-
 TEST_F(GCMProfileServiceSingleProfileTest, Register) {
   std::vector<std::string> sender_ids;
   sender_ids.push_back("sender1");
@@ -766,6 +869,7 @@ TEST_F(GCMProfileServiceSingleProfileTest, ReadRegistrationFromStateStore) {
 
   // This should read the registration info from the extension's state store.
   consumer()->Register(extension->id(), sender_ids);
+  PumpIOLoop();
   PumpUILoop();
   EXPECT_EQ(old_registration_id, consumer()->registration_id());
   EXPECT_EQ(GCMClient::SUCCESS, consumer()->registration_result());
@@ -788,10 +892,8 @@ TEST_F(GCMProfileServiceSingleProfileTest,
   // preparation to call register 2nd time.
   consumer()->clear_registration_result();
 
-  // Needs to create a GCMClient instance that is not ready initiallly.
-  consumer()->set_gcm_client_initial_status(GCMClientMock::NOT_READY);
-
   // Simulate start-up by recreating GCMProfileService.
+  consumer()->set_gcm_client_loading_delay(GCMClientMock::DELAY_LOADING);
   consumer()->CreateGCMProfileServiceInstance();
 
   // Simulate start-up by reloading extension.
@@ -805,7 +907,7 @@ TEST_F(GCMProfileServiceSingleProfileTest,
   EXPECT_EQ(GCMClient::UNKNOWN_ERROR, consumer()->registration_result());
 
   // Register operation will be invoked after GCMClient becomes ready.
-  consumer()->GetGCMClient()->SetReady();
+  consumer()->GetGCMClient()->PerformDelayedLoading();
   WaitUntilCompleted();
   EXPECT_EQ(old_registration_id, consumer()->registration_id());
   EXPECT_EQ(GCMClient::SUCCESS, consumer()->registration_result());
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 09090fd..cfe8726 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -1082,6 +1082,8 @@ void ProfileSyncService::OnExperimentsChanged(
                                       experiments.gcm_channel_state ==
                                           syncer::Experiments::ENABLED);
     gcm::GCMProfileServiceFactory::GetForProfile(profile());
+  } else {
+    profile()->GetPrefs()->ClearPref(prefs::kGCMChannelEnabled);
   }
 
   if (experiments.enhanced_bookmarks_enabled) {
diff --git a/chrome/browser/sync/profile_sync_service_factory.cc b/chrome/browser/sync/profile_sync_service_factory.cc
index 6e2f869..421fa01 100644
--- a/chrome/browser/sync/profile_sync_service_factory.cc
+++ b/chrome/browser/sync/profile_sync_service_factory.cc
@@ -95,16 +95,10 @@ BrowserContextKeyedService* ProfileSyncServiceFactory::BuildServiceInstanceFor(
 
   SigninManagerBase* signin = SigninManagerFactory::GetForProfile(profile);
 
-  // Automatically load the GCMProfileService if the enabled state has been
-  // explicitly set.
-  const base::Value* gcm_enabled_value =
-      profile->GetPrefs()->GetUserPrefValue(prefs::kGCMChannelEnabled);
-  bool gcm_enabled = false;
-  if (gcm_enabled_value &&
-      gcm_enabled_value->GetAsBoolean(&gcm_enabled) &&
-      gcm_enabled) {
-    gcm::GCMProfileServiceFactory::GetForProfile(profile);
-  }
+  // Always create the GCMProfileService instance such that we can listen to
+  // the profile notifications and purge the GCM store when the profile is
+  // being signed out.
+  gcm::GCMProfileServiceFactory::GetForProfile(profile);
 
   // TODO(atwilson): Change AboutSigninInternalsFactory to load on startup
   // once http://crbug.com/171406 has been fixed.
diff --git a/google_apis/gcm/engine/mcs_client.cc b/google_apis/gcm/engine/mcs_client.cc
index adae939..dbfa7ff 100644
--- a/google_apis/gcm/engine/mcs_client.cc
+++ b/google_apis/gcm/engine/mcs_client.cc
@@ -335,11 +335,6 @@ void MCSClient::SendMessage(const MCSMessage& message) {
   MaybeSendMessage();
 }
 
-void MCSClient::Destroy() {
-  gcm_store_->Destroy(base::Bind(&MCSClient::OnGCMUpdateFinished,
-                                 weak_ptr_factory_.GetWeakPtr()));
-}
-
 void MCSClient::ResetStateAndBuildLoginRequest(
     mcs_proto::LoginRequest* request) {
   DCHECK(android_id_);
diff --git a/google_apis/gcm/engine/mcs_client.h b/google_apis/gcm/engine/mcs_client.h
index a81643b..f254566 100644
--- a/google_apis/gcm/engine/mcs_client.h
+++ b/google_apis/gcm/engine/mcs_client.h
@@ -122,13 +122,6 @@ class GCM_EXPORT MCSClient {
   // |message_sent_callback_| is invoked with a TTL expiration error.
   virtual void SendMessage(const MCSMessage& message);
 
-  // Disconnects the client and permanently destroys the persistent GCM store.
-  // WARNING: This is permanent, and the client must be recreated with new
-  // credentials afterwards.
-  // TODO(jianli): destroying the persistent GCM store should be moved to
-  // GCMClient.
-  void Destroy();
-
   // Returns the current state of the client.
   State state() const { return state_; }
 
diff --git a/google_apis/gcm/gcm_client.h b/google_apis/gcm/gcm_client.h
index 8bb616d..962486f 100644
--- a/google_apis/gcm/gcm_client.h
+++ b/google_apis/gcm/gcm_client.h
@@ -132,7 +132,8 @@ class GCM_EXPORT GCMClient {
   GCMClient();
   virtual ~GCMClient();
 
-  // Begins initialization of the GCM Client.
+  // Begins initialization of the GCM Client. This will not trigger a
+  // connection.
   // |chrome_build_proto|: chrome info, i.e., version, channel and etc.
   // |store_path|: path to the GCM store.
   // |blocking_task_runner|: for running blocking file tasks.
@@ -147,6 +148,10 @@ class GCM_EXPORT GCMClient {
           url_request_context_getter,
       Delegate* delegate) = 0;
 
+  // Loads the data from the persistent store. This will automatically kick off
+  // the check-in if the check-in info is not found in the store.
+  virtual void Load() = 0;
+
   // Checks out of the GCM service. This will erase all the cached and persisted
   // data.
   virtual void CheckOut() = 0;
@@ -176,9 +181,6 @@ class GCM_EXPORT GCMClient {
   virtual void Send(const std::string& app_id,
                     const std::string& receiver_id,
                     const OutgoingMessage& message) = 0;
-
-  // Returns true if GCM becomes ready.
-  virtual bool IsReady() const = 0;
 };
 
 }  // namespace gcm
diff --git a/google_apis/gcm/gcm_client_impl.cc b/google_apis/gcm/gcm_client_impl.cc
index 491599c..6aa733e 100644
--- a/google_apis/gcm/gcm_client_impl.cc
+++ b/google_apis/gcm/gcm_client_impl.cc
@@ -9,6 +9,7 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
 #include "base/sequenced_task_runner.h"
 #include "base/time/default_clock.h"
 #include "google_apis/gcm/base/mcs_message.h"
@@ -138,30 +139,18 @@ void GCMClientImpl::Initialize(
   url_request_context_getter_ = url_request_context_getter;
 
   gcm_store_.reset(new GCMStoreImpl(false, path, blocking_task_runner));
-  gcm_store_->Load(base::Bind(&GCMClientImpl::OnLoadCompleted,
-                              weak_ptr_factory_.GetWeakPtr()));
 
   delegate_ = delegate;
 
-  // |mcs_client_| might already be set for testing at this point. No need to
-  // create a |connection_factory_|.
-  if (!mcs_client_.get()) {
-    const net::HttpNetworkSession::Params* network_session_params =
-        url_request_context_getter->GetURLRequestContext()->
-            GetNetworkSessionParams();
-    DCHECK(network_session_params);
-    network_session_ = new net::HttpNetworkSession(*network_session_params);
-    connection_factory_.reset(new ConnectionFactoryImpl(
-        GURL(kMCSEndpoint),
-        kDefaultBackoffPolicy,
-        network_session_,
-        net_log_.net_log()));
-    mcs_client_.reset(new MCSClient(chrome_build_proto.chrome_version(),
-                                    clock_.get(),
-                                    connection_factory_.get(),
-                                    gcm_store_.get()));
-  }
+  state_ = INITIALIZED;
+}
+
+void GCMClientImpl::Load() {
+  DCHECK_EQ(INITIALIZED, state_);
 
+  // Once the loading is completed, the check-in will be initiated.
+  gcm_store_->Load(base::Bind(&GCMClientImpl::OnLoadCompleted,
+                              weak_ptr_factory_.GetWeakPtr()));
   state_ = LOADING;
 }
 
@@ -188,6 +177,25 @@ void GCMClientImpl::OnLoadCompleted(scoped_ptr<GCMStore::LoadResult> result) {
 
 void GCMClientImpl::InitializeMCSClient(
     scoped_ptr<GCMStore::LoadResult> result) {
+  // |mcs_client_| might already be set for testing at this point. No need to
+  // create a |connection_factory_|.
+  if (!mcs_client_.get()) {
+    const net::HttpNetworkSession::Params* network_session_params =
+        url_request_context_getter_->GetURLRequestContext()->
+            GetNetworkSessionParams();
+    DCHECK(network_session_params);
+    network_session_ = new net::HttpNetworkSession(*network_session_params);
+    connection_factory_.reset(new ConnectionFactoryImpl(
+        GURL(kMCSEndpoint),
+        kDefaultBackoffPolicy,
+        network_session_,
+        net_log_.net_log()));
+    mcs_client_.reset(new MCSClient(chrome_build_proto_.chrome_version(),
+                                    clock_.get(),
+                                    connection_factory_.get(),
+                                    gcm_store_.get()));
+  }
+
   mcs_client_->Initialize(
       base::Bind(&GCMClientImpl::OnMCSError, weak_ptr_factory_.GetWeakPtr()),
       base::Bind(&GCMClientImpl::OnMessageReceivedFromMCS,
@@ -276,12 +284,13 @@ void GCMClientImpl::SetDeviceCredentialsCallback(bool success) {
 }
 
 void GCMClientImpl::CheckOut() {
-  delegate_ = NULL;
   device_checkin_info_.Reset();
-  mcs_client_->Destroy();  // This will also destroy GCM store.
   mcs_client_.reset();
+  gcm_store_->Destroy(base::Bind(&GCMClientImpl::OnGCMStoreDestroyed,
+                                 weak_ptr_factory_.GetWeakPtr()));
   checkin_request_.reset();
   pending_registrations_.clear();
+  state_ = INITIALIZED;
 }
 
 void GCMClientImpl::Register(const std::string& app_id,
@@ -368,6 +377,11 @@ void GCMClientImpl::OnUnregisterCompleted(const std::string& app_id,
   pending_unregistrations_.erase(iter);
 }
 
+void GCMClientImpl::OnGCMStoreDestroyed(bool success) {
+  DLOG_IF(ERROR, !success) << "GCM store failed to be destroyed!";
+  UMA_HISTOGRAM_BOOLEAN("GCM.StoreDestroySucceeded", success);
+}
+
 void GCMClientImpl::Send(const std::string& app_id,
                          const std::string& receiver_id,
                          const OutgoingMessage& message) {
@@ -395,10 +409,6 @@ void GCMClientImpl::Send(const std::string& app_id,
   mcs_client_->SendMessage(mcs_message);
 }
 
-bool GCMClientImpl::IsReady() const {
-  return state_ == READY;
-}
-
 void GCMClientImpl::OnMessageReceivedFromMCS(const gcm::MCSMessage& message) {
   switch (message.tag()) {
     case kLoginResponseTag:
diff --git a/google_apis/gcm/gcm_client_impl.h b/google_apis/gcm/gcm_client_impl.h
index 40b90f2..6feedbf 100644
--- a/google_apis/gcm/gcm_client_impl.h
+++ b/google_apis/gcm/gcm_client_impl.h
@@ -54,6 +54,7 @@ class GCM_EXPORT GCMClientImpl : public GCMClient {
       const scoped_refptr<net::URLRequestContextGetter>&
           url_request_context_getter,
       Delegate* delegate) OVERRIDE;
+  virtual void Load() OVERRIDE;
   virtual void CheckOut() OVERRIDE;
   virtual void Register(const std::string& app_id,
                         const std::string& cert,
@@ -62,13 +63,14 @@ class GCM_EXPORT GCMClientImpl : public GCMClient {
   virtual void Send(const std::string& app_id,
                     const std::string& receiver_id,
                     const OutgoingMessage& message) OVERRIDE;
-  virtual bool IsReady() const OVERRIDE;
 
  private:
   // State representation of the GCMClient.
   enum State {
     // Uninitialized.
     UNINITIALIZED,
+    // Initialized,
+    INITIALIZED,
     // GCM store loading is in progress.
     LOADING,
     // Initial device checkin is in progress.
@@ -149,6 +151,9 @@ class GCM_EXPORT GCMClientImpl : public GCMClient {
   // Completes the unregistration request.
   void OnUnregisterCompleted(const std::string& app_id, bool status);
 
+  // Completes the GCM store destroy request.
+  void OnGCMStoreDestroyed(bool success);
+
   // Handles incoming data message and dispatches it the a relevant user
   // delegate.
   void HandleIncomingMessage(const gcm::MCSMessage& message);
diff --git a/google_apis/gcm/gcm_client_impl_unittest.cc b/google_apis/gcm/gcm_client_impl_unittest.cc
index f2364f4..a78e1a6 100644
--- a/google_apis/gcm/gcm_client_impl_unittest.cc
+++ b/google_apis/gcm/gcm_client_impl_unittest.cc
@@ -283,10 +283,15 @@ void GCMClientImplTest::InitializeGCMClient() {
                           message_loop_.message_loop_proxy(),
                           url_request_context_getter_,
                           this);
+
 #if defined(OS_MACOSX)
   // On OSX, prevent the Keychain permissions popup during unit tests.
   Encryptor::UseMockKeychain(true);  // Must be after Initialize.
 #endif
+
+  // Starting loading and check-in.
+  gcm_client_->Load();
+
   // Ensuring that mcs_client is using the same gcm_store as gcm_client.
   mcs_client()->set_gcm_store(gcm_client_->gcm_store_.get());
   PumpLoopUntilIdle();
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 5b98b10..3b3047c 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -5588,6 +5588,14 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="GCM.StoreDestroySucceeded" enum="BooleanSuccess">
+  <summary>
+    Success indicates successfully destroying the GCM persistent store. Failure
+    indicates a failure destroying the persistence store. GCM store will be
+    destroyed when the profile has been signed out.
+  </summary>
+</histogram>
+
 <histogram name="GCM.StoreLoadSucceeded" enum="BooleanSuccess">
   <summary>
     Success indicates successfully loading an initialized persistent GCM store