Reland: Add GCMChannelStatusSyncer to schedule requests and enable/disable GCM

BUG=384041
TEST=new tests added

Committed: https://crrev.com/3c23f4a188e171998f3042ad62f4aa5717e66d63
Cr-Commit-Position: refs/heads/master@{#295524}

Review URL: https://codereview.chromium.org/561943002

Cr-Commit-Position: refs/heads/master@{#295645}

10 files changed, 593 insertions, 21 deletions

diff --git a/components/gcm_driver/BUILD.gn b/components/gcm_driver/BUILD.gn
index a446c9f..9e4f3d7 100644
--- a/components/gcm_driver/BUILD.gn
+++ b/components/gcm_driver/BUILD.gn
@@ -17,6 +17,8 @@ static_library("gcm_driver") {
     "gcm_backoff_policy.h",
     "gcm_channel_status_request.cc",
     "gcm_channel_status_request.h",
+    "gcm_channel_status_syncer.cc",
+    "gcm_channel_status_syncer.h",
     "gcm_client.cc",
     "gcm_client.h",
     "gcm_client_factory.cc",
@@ -51,6 +53,8 @@ static_library("gcm_driver") {
     sources -= [
       "gcm_channel_status_request.cc",
       "gcm_channel_status_request.h",
+      "gcm_channel_status_syncer.cc",
+      "gcm_channel_status_syncer.h",
       "gcm_client_factory.cc",
       "gcm_client_factory.h",
       "gcm_client_impl.cc",
diff --git a/components/gcm_driver/DEPS b/components/gcm_driver/DEPS
index cbffdad..93923ff 100644
--- a/components/gcm_driver/DEPS
+++ b/components/gcm_driver/DEPS
@@ -1,5 +1,6 @@
 include_rules = [
   "+components/os_crypt",
+  "+components/pref_registry",
   # TODO(johnme): Fix this layering violation.
   "!content/public/android/java",
   "+google_apis/gaia",
diff --git a/components/gcm_driver/gcm_channel_status_request.cc b/components/gcm_driver/gcm_channel_status_request.cc
index 206ee39..fd405d1 100644
--- a/components/gcm_driver/gcm_channel_status_request.cc
+++ b/components/gcm_driver/gcm_channel_status_request.cc
@@ -41,12 +41,12 @@ GCMChannelStatusRequest::~GCMChannelStatusRequest() {
 }
 
 // static
-int GCMChannelStatusRequest::default_poll_interval_seconds_for_testing() {
+int GCMChannelStatusRequest::default_poll_interval_seconds() {
   return kDefaultPollIntervalSeconds;
 }
 
 // static
-int GCMChannelStatusRequest::min_poll_interval_seconds_for_testing() {
+int GCMChannelStatusRequest::min_poll_interval_seconds() {
   return kMinPollIntervalSeconds;
 }
 
diff --git a/components/gcm_driver/gcm_channel_status_request.h b/components/gcm_driver/gcm_channel_status_request.h
index b2725759..6ce1bab 100644
--- a/components/gcm_driver/gcm_channel_status_request.h
+++ b/components/gcm_driver/gcm_channel_status_request.h
@@ -36,9 +36,8 @@ class GCMChannelStatusRequest : public net::URLFetcherDelegate {
 
   void Start();
 
-  // Exposed for testing purpose.
-  static int default_poll_interval_seconds_for_testing();
-  static int min_poll_interval_seconds_for_testing();
+  static int default_poll_interval_seconds();
+  static int min_poll_interval_seconds();
 
  private:
   // Overridden from URLFetcherDelegate:
diff --git a/components/gcm_driver/gcm_channel_status_request_unittest.cc b/components/gcm_driver/gcm_channel_status_request_unittest.cc
index daf8122..961ca4e 100644
--- a/components/gcm_driver/gcm_channel_status_request_unittest.cc
+++ b/components/gcm_driver/gcm_channel_status_request_unittest.cc
@@ -136,7 +136,7 @@ TEST_F(GCMChannelStatusRequestTest, ResponseWithDisabledStatus) {
   EXPECT_TRUE(request_callback_invoked_);
   EXPECT_FALSE(enabled_);
   EXPECT_EQ(
-      GCMChannelStatusRequest::default_poll_interval_seconds_for_testing(),
+      GCMChannelStatusRequest::default_poll_interval_seconds(),
       poll_interval_seconds_);
 }
 
@@ -148,7 +148,7 @@ TEST_F(GCMChannelStatusRequestTest, ResponseWithEnabledStatus) {
   EXPECT_TRUE(request_callback_invoked_);
   EXPECT_TRUE(enabled_);
   EXPECT_EQ(
-      GCMChannelStatusRequest::default_poll_interval_seconds_for_testing(),
+      GCMChannelStatusRequest::default_poll_interval_seconds(),
       poll_interval_seconds_);
 }
 
@@ -156,8 +156,7 @@ TEST_F(GCMChannelStatusRequestTest, ResponseWithPollInterval) {
   // Setting a poll interval 15 minutes longer than the minimum interval we
   // enforce.
   int poll_interval_seconds =
-      GCMChannelStatusRequest::min_poll_interval_seconds_for_testing() +
-      15 * 60;
+      GCMChannelStatusRequest::min_poll_interval_seconds() + 15 * 60;
   StartRequest();
   SetResponseProtoData(NOT_SPECIFIED, poll_interval_seconds);
   CompleteFetch();
@@ -171,22 +170,20 @@ TEST_F(GCMChannelStatusRequestTest, ResponseWithShortPollInterval) {
   // Setting a poll interval 15 minutes shorter than the minimum interval we
   // enforce.
   int poll_interval_seconds =
-      GCMChannelStatusRequest::min_poll_interval_seconds_for_testing() -
-      15 * 60;
+      GCMChannelStatusRequest::min_poll_interval_seconds() - 15 * 60;
   StartRequest();
   SetResponseProtoData(NOT_SPECIFIED, poll_interval_seconds);
   CompleteFetch();
 
   EXPECT_TRUE(request_callback_invoked_);
   EXPECT_TRUE(enabled_);
-  EXPECT_EQ(GCMChannelStatusRequest::min_poll_interval_seconds_for_testing(),
+  EXPECT_EQ(GCMChannelStatusRequest::min_poll_interval_seconds(),
             poll_interval_seconds_);
 }
 
 TEST_F(GCMChannelStatusRequestTest, ResponseWithDisabledStatusAndPollInterval) {
   int poll_interval_seconds =
-      GCMChannelStatusRequest::min_poll_interval_seconds_for_testing() +
-      15 * 60;
+      GCMChannelStatusRequest::min_poll_interval_seconds() + 15 * 60;
   StartRequest();
   SetResponseProtoData(GCM_DISABLED, poll_interval_seconds);
   CompleteFetch();
diff --git a/components/gcm_driver/gcm_channel_status_syncer.cc b/components/gcm_driver/gcm_channel_status_syncer.cc
new file mode 100644
index 0000000..7006721
--- /dev/null
+++ b/components/gcm_driver/gcm_channel_status_syncer.cc
@@ -0,0 +1,183 @@
+// Copyright 2014 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 "components/gcm_driver/gcm_channel_status_syncer.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
+#include "base/rand_util.h"
+#include "components/gcm_driver/gcm_channel_status_request.h"
+#include "components/gcm_driver/gcm_driver.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+
+namespace gcm {
+
+namespace {
+
+// The GCM channel's enabled state.
+const char kGCMChannelStatus[] = "gcm.channel_status";
+
+// The GCM channel's polling interval (in seconds).
+const char kGCMChannelPollIntervalSeconds[] = "gcm.poll_interval";
+
+// Last time when checking with the GCM channel status server is done.
+const char kGCMChannelLastCheckTime[] = "gcm.check_time";
+
+// A small delay to avoid sending request at browser startup time for first-time
+// request.
+const int kFirstTimeDelaySeconds = 1 * 60;  // 1 minute.
+
+// The fuzzing variation added to the polling delay.
+const int kGCMChannelRequestTimeJitterSeconds = 15 * 60;  // 15 minues.
+
+}  // namespace
+
+// static
+void GCMChannelStatusSyncer::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterBooleanPref(kGCMChannelStatus, true);
+  registry->RegisterIntegerPref(
+      kGCMChannelPollIntervalSeconds,
+      GCMChannelStatusRequest::default_poll_interval_seconds());
+  registry->RegisterInt64Pref(kGCMChannelLastCheckTime, 0);
+}
+
+// static
+void GCMChannelStatusSyncer::RegisterProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterBooleanPref(
+      kGCMChannelStatus,
+      true,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  registry->RegisterIntegerPref(
+      kGCMChannelPollIntervalSeconds,
+      GCMChannelStatusRequest::default_poll_interval_seconds(),
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  registry->RegisterInt64Pref(
+      kGCMChannelLastCheckTime,
+      0,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+}
+
+// static
+int GCMChannelStatusSyncer::first_time_delay_seconds() {
+  return kFirstTimeDelaySeconds;
+}
+
+GCMChannelStatusSyncer::GCMChannelStatusSyncer(
+    GCMDriver* driver,
+    PrefService* prefs,
+    const scoped_refptr<net::URLRequestContextGetter>& request_context)
+    : driver_(driver),
+      prefs_(prefs),
+      request_context_(request_context),
+      gcm_enabled_(true),
+      poll_interval_seconds_(
+          GCMChannelStatusRequest::default_poll_interval_seconds()),
+      delay_removed_for_testing_(false),
+      weak_ptr_factory_(this) {
+  gcm_enabled_ = prefs_->GetBoolean(kGCMChannelStatus);
+  poll_interval_seconds_ = prefs_->GetInteger(kGCMChannelPollIntervalSeconds);
+  if (poll_interval_seconds_ <
+      GCMChannelStatusRequest::min_poll_interval_seconds()) {
+    poll_interval_seconds_ =
+        GCMChannelStatusRequest::min_poll_interval_seconds();
+  }
+  last_check_time_ = base::Time::FromInternalValue(
+      prefs_->GetInt64(kGCMChannelLastCheckTime));
+}
+
+GCMChannelStatusSyncer::~GCMChannelStatusSyncer() {
+}
+
+void GCMChannelStatusSyncer::EnsureStarted() {
+  // Bail out if the request is already scheduled or started.
+  if (weak_ptr_factory_.HasWeakPtrs() || request_)
+    return;
+
+  ScheduleRequest();
+}
+
+void GCMChannelStatusSyncer::Stop() {
+  request_.reset();
+  weak_ptr_factory_.InvalidateWeakPtrs();
+}
+
+void GCMChannelStatusSyncer::OnRequestCompleted(bool enabled,
+                                                int poll_interval_seconds) {
+  DCHECK(request_);
+  request_.reset();
+
+  // Persist the current time as the last request complete time.
+  last_check_time_ = base::Time::Now();
+  prefs_->SetInt64(kGCMChannelLastCheckTime,
+                   last_check_time_.ToInternalValue());
+
+  if (gcm_enabled_ != enabled) {
+    gcm_enabled_ = enabled;
+    prefs_->SetBoolean(kGCMChannelStatus, enabled);
+    if (gcm_enabled_)
+      driver_->Enable();
+    else
+      driver_->Disable();
+  }
+
+  DCHECK_GE(poll_interval_seconds,
+            GCMChannelStatusRequest::min_poll_interval_seconds());
+  if (poll_interval_seconds_ != poll_interval_seconds) {
+    poll_interval_seconds_ = poll_interval_seconds;
+    prefs_->SetInteger(kGCMChannelPollIntervalSeconds, poll_interval_seconds_);
+  }
+
+  ScheduleRequest();
+}
+
+void GCMChannelStatusSyncer::ScheduleRequest() {
+  current_request_delay_interval_ = GetRequestDelayInterval();
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&GCMChannelStatusSyncer::StartRequest,
+                 weak_ptr_factory_.GetWeakPtr()),
+      current_request_delay_interval_);
+}
+
+void GCMChannelStatusSyncer::StartRequest() {
+  DCHECK(!request_);
+
+  request_.reset(new GCMChannelStatusRequest(
+      request_context_,
+      base::Bind(&GCMChannelStatusSyncer::OnRequestCompleted,
+                 weak_ptr_factory_.GetWeakPtr())));
+  request_->Start();
+}
+
+base::TimeDelta GCMChannelStatusSyncer::GetRequestDelayInterval() const {
+  // No delay during testing.
+  if (delay_removed_for_testing_)
+    return base::TimeDelta();
+
+  // Make sure that checking with server occurs at polling interval, regardless
+  // whether the browser restarts.
+  int64 delay_seconds = poll_interval_seconds_ -
+      (base::Time::Now() - last_check_time_).InSeconds();
+  if (delay_seconds < 0)
+    delay_seconds = 0;
+
+  if (last_check_time_.is_null()) {
+    // For the first-time request, add a small delay to avoid sending request at
+    // browser startup time.
+    DCHECK(!delay_seconds);
+    delay_seconds = kFirstTimeDelaySeconds;
+  } else {
+    // Otherwise, add a fuzzing variation to the delay.
+    delay_seconds += base::RandInt(0, kGCMChannelRequestTimeJitterSeconds);
+  }
+
+  return base::TimeDelta::FromSeconds(delay_seconds);
+}
+
+}  // namespace gcm
diff --git a/components/gcm_driver/gcm_channel_status_syncer.h b/components/gcm_driver/gcm_channel_status_syncer.h
new file mode 100644
index 0000000..83cfbda3
--- /dev/null
+++ b/components/gcm_driver/gcm_channel_status_syncer.h
@@ -0,0 +1,98 @@
+// Copyright 2014 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 COMPONENTS_GCM_DRIVER_GCM_CHANNEL_STATUS_SYNCER_H_
+#define COMPONENTS_GCM_DRIVER_GCM_CHANNEL_STATUS_SYNCER_H_
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+
+class PrefService;
+class PrefRegistrySimple;
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
+namespace gcm {
+
+class GCMChannelStatusRequest;
+class GCMDriver;
+
+// Syncing with the server for GCM channel status that controls if GCM
+// functionality should be enabled or disabled.
+class GCMChannelStatusSyncer {
+ public:
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
+
+  GCMChannelStatusSyncer(
+      GCMDriver* driver,
+      PrefService* prefs,
+      const scoped_refptr<net::URLRequestContextGetter>& request_context);
+  ~GCMChannelStatusSyncer();
+
+  void EnsureStarted();
+  void Stop();
+
+  bool gcm_enabled() const { return gcm_enabled_; }
+
+  // For testing purpose.
+  void set_delay_removed_for_testing(bool delay_removed) {
+    delay_removed_for_testing_ = delay_removed;
+  }
+  base::TimeDelta current_request_delay_interval() const {
+    return current_request_delay_interval_;
+  }
+  static int first_time_delay_seconds();
+
+ private:
+  // Called when a request is completed.
+  void OnRequestCompleted(bool enabled, int poll_interval_seconds);
+
+  // Schedules next request to start after appropriate delay.
+  void ScheduleRequest();
+
+  // Creates and starts a request immediately.
+  void StartRequest();
+
+  // Computes and returns a delay with the fuzzing variation added if needed,
+  // after which the request could start.
+  base::TimeDelta GetRequestDelayInterval() const;
+
+  // GCMDriver owns GCMChannelStatusSyncer instance.
+  GCMDriver* driver_;
+  PrefService* prefs_;
+
+  scoped_refptr<net::URLRequestContextGetter> request_context_;
+  scoped_ptr<GCMChannelStatusRequest> request_;
+
+  bool gcm_enabled_;
+  int poll_interval_seconds_;
+  base::Time last_check_time_;
+
+  // The flag that indicates if the delay, including fuzzing variation and poll
+  // interval, is removed for testing purpose.
+  bool delay_removed_for_testing_;
+
+  // Tracked for testing purpose.
+  base::TimeDelta current_request_delay_interval_;
+
+  // Used to pass a weak pointer to a task.
+  base::WeakPtrFactory<GCMChannelStatusSyncer> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(GCMChannelStatusSyncer);
+};
+
+}  // namespace gcm
+
+#endif  // COMPONENTS_GCM_DRIVER_GCM_CHANNEL_STATUS_SYNCER_H_
diff --git a/components/gcm_driver/gcm_driver_desktop.cc b/components/gcm_driver/gcm_driver_desktop.cc
index 8d35c2c..82ca4b3 100644
--- a/components/gcm_driver/gcm_driver_desktop.cc
+++ b/components/gcm_driver/gcm_driver_desktop.cc
@@ -14,6 +14,7 @@
 #include "base/sequenced_task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "components/gcm_driver/gcm_app_handler.h"
+#include "components/gcm_driver/gcm_channel_status_syncer.h"
 #include "components/gcm_driver/gcm_client_factory.h"
 #include "components/gcm_driver/gcm_delayed_task_controller.h"
 #include "components/gcm_driver/system_encryptor.h"
@@ -329,18 +330,23 @@ void GCMDriverDesktop::IOWorker::RemoveAccountMapping(
 GCMDriverDesktop::GCMDriverDesktop(
     scoped_ptr<GCMClientFactory> gcm_client_factory,
     const GCMClient::ChromeBuildInfo& chrome_build_info,
+    PrefService* prefs,
     const base::FilePath& store_path,
     const scoped_refptr<net::URLRequestContextGetter>& request_context,
     const scoped_refptr<base::SequencedTaskRunner>& ui_thread,
     const scoped_refptr<base::SequencedTaskRunner>& io_thread,
     const scoped_refptr<base::SequencedTaskRunner>& blocking_task_runner)
-    : signed_in_(false),
+    : gcm_channel_status_syncer_(
+          new GCMChannelStatusSyncer(this, prefs, request_context)),
+      signed_in_(false),
       gcm_started_(false),
       gcm_enabled_(true),
       connected_(false),
       ui_thread_(ui_thread),
       io_thread_(io_thread),
       weak_ptr_factory_(this) {
+  gcm_enabled_ = gcm_channel_status_syncer_->gcm_enabled();
+
   // Create and initialize the GCMClient. Note that this does not initiate the
   // GCM check-in.
   io_worker_.reset(new IOWorker(ui_thread, io_thread));
@@ -361,6 +367,12 @@ GCMDriverDesktop::~GCMDriverDesktop() {
 void GCMDriverDesktop::Shutdown() {
   DCHECK(ui_thread_->RunsTasksOnCurrentThread());
   GCMDriver::Shutdown();
+
+  // Dispose the syncer in order to release the reference to
+  // URLRequestContextGetter that needs to be done before IOThread gets
+  // deleted.
+  gcm_channel_status_syncer_.reset();
+
   io_thread_->DeleteSoon(FROM_HERE, io_worker_.release());
 }
 
@@ -442,6 +454,8 @@ void GCMDriverDesktop::Stop() {
   if (!gcm_started_)
     return;
 
+  gcm_channel_status_syncer_->Stop();
+
   RemoveCachedData();
 
   io_thread_->PostTask(
@@ -627,6 +641,11 @@ GCMClient::Result GCMDriverDesktop::EnsureStarted() {
   DCHECK(!delayed_task_controller_);
   delayed_task_controller_.reset(new GCMDelayedTaskController);
 
+  // Polling for channel status is only needed when GCM is supported for all
+  // users.
+  if (GCMDriver::IsAllowedForAllUsers())
+    gcm_channel_status_syncer_->EnsureStarted();
+
   // Note that we need to pass weak pointer again since the existing weak
   // pointer in IOWorker might have been invalidated when check-out occurs.
   io_thread_->PostTask(
diff --git a/components/gcm_driver/gcm_driver_desktop.h b/components/gcm_driver/gcm_driver_desktop.h
index 51a9845..0ef9495 100644
--- a/components/gcm_driver/gcm_driver_desktop.h
+++ b/components/gcm_driver/gcm_driver_desktop.h
@@ -15,10 +15,13 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "components/gcm_driver/gcm_channel_status_syncer.h"
 #include "components/gcm_driver/gcm_client.h"
 #include "components/gcm_driver/gcm_connection_observer.h"
 #include "components/gcm_driver/gcm_driver.h"
 
+class PrefService;
+
 namespace base {
 class FilePath;
 class SequencedTaskRunner;
@@ -44,6 +47,7 @@ class GCMDriverDesktop : public GCMDriver {
   GCMDriverDesktop(
       scoped_ptr<GCMClientFactory> gcm_client_factory,
       const GCMClient::ChromeBuildInfo& chrome_build_info,
+      PrefService* prefs,
       const base::FilePath& store_path,
       const scoped_refptr<net::URLRequestContextGetter>& request_context,
       const scoped_refptr<base::SequencedTaskRunner>& ui_thread,
@@ -84,6 +88,12 @@ class GCMDriverDesktop : public GCMDriver {
   void SetAccountsForCheckin(
       const std::map<std::string, std::string>& account_tokens);
 
+  // Exposed for testing purpose.
+  bool gcm_enabled() const { return gcm_enabled_; }
+  GCMChannelStatusSyncer* gcm_channel_status_syncer_for_testing() {
+    return gcm_channel_status_syncer_.get();
+  }
+
  protected:
   // GCMDriver implementation:
   virtual GCMClient::Result EnsureStarted() OVERRIDE;
@@ -125,6 +135,8 @@ class GCMDriverDesktop : public GCMDriver {
 
   void GetGCMStatisticsFinished(const GCMClient::GCMStatistics& stats);
 
+  scoped_ptr<GCMChannelStatusSyncer> gcm_channel_status_syncer_;
+
   // Flag to indicate whether the user is signed in to a GAIA account.
   // TODO(jianli): To be removed when sign-in enforcement is dropped.
   bool signed_in_;
@@ -133,6 +145,7 @@ class GCMDriverDesktop : public GCMDriver {
   bool gcm_started_;
 
   // Flag to indicate if GCM is enabled.
+  // TODO(jianli): Removed when we switch completely to support all users.
   bool gcm_enabled_;
 
   // Flag to indicate the last known state of the GCM client. Because this
diff --git a/components/gcm_driver/gcm_driver_desktop_unittest.cc b/components/gcm_driver/gcm_driver_desktop_unittest.cc
index ad95f86..8a25768 100644
--- a/components/gcm_driver/gcm_driver_desktop_unittest.cc
+++ b/components/gcm_driver/gcm_driver_desktop_unittest.cc
@@ -11,6 +11,8 @@
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/metrics/field_trial.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/testing_pref_service.h"
 #include "base/run_loop.h"
 #include "base/strings/string_util.h"
 #include "base/test/test_simple_task_runner.h"
@@ -19,8 +21,13 @@
 #include "components/gcm_driver/fake_gcm_client.h"
 #include "components/gcm_driver/fake_gcm_client_factory.h"
 #include "components/gcm_driver/gcm_app_handler.h"
+#include "components/gcm_driver/gcm_channel_status_request.h"
+#include "components/gcm_driver/gcm_channel_status_syncer.h"
 #include "components/gcm_driver/gcm_client_factory.h"
 #include "components/gcm_driver/gcm_connection_observer.h"
+#include "components/gcm_driver/proto/gcm_channel_status.pb.h"
+#include "net/url_request/test_url_fetcher_factory.h"
+#include "net/url_request/url_fetcher_delegate.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -97,7 +104,7 @@ class GCMDriverTest : public testing::Test {
   virtual void SetUp() OVERRIDE;
   virtual void TearDown() OVERRIDE;
 
-  GCMDriver* driver() { return driver_.get(); }
+  GCMDriverDesktop* driver() { return driver_.get(); }
   FakeGCMAppHandler* gcm_app_handler() { return gcm_app_handler_.get(); }
   FakeGCMConnectionObserver* gcm_connection_observer() {
     return gcm_connection_observer_.get();
@@ -118,6 +125,7 @@ class GCMDriverTest : public testing::Test {
   FakeGCMClient* GetGCMClient();
 
   void CreateDriver(FakeGCMClient::StartMode gcm_client_start_mode);
+  void ShutdownDriver();
   void AddAppHandlers();
   void RemoveAppHandlers();
 
@@ -142,11 +150,12 @@ class GCMDriverTest : public testing::Test {
   void UnregisterCompleted(GCMClient::Result result);
 
   base::ScopedTempDir temp_dir_;
+  TestingPrefServiceSimple prefs_;
   scoped_refptr<base::TestSimpleTaskRunner> task_runner_;
   base::MessageLoopForUI message_loop_;
   base::Thread io_thread_;
   base::FieldTrialList field_trial_list_;
-  scoped_ptr<GCMDriver> driver_;
+  scoped_ptr<GCMDriverDesktop> driver_;
   scoped_ptr<FakeGCMAppHandler> gcm_app_handler_;
   scoped_ptr<FakeGCMConnectionObserver> gcm_connection_observer_;
 
@@ -174,6 +183,7 @@ GCMDriverTest::~GCMDriverTest() {
 }
 
 void GCMDriverTest::SetUp() {
+  GCMChannelStatusSyncer::RegisterPrefs(prefs_.registry());
   io_thread_.Start();
   ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
 }
@@ -182,9 +192,7 @@ void GCMDriverTest::TearDown() {
   if (!driver_)
     return;
 
-  if (gcm_connection_observer_.get())
-    driver_->RemoveConnectionObserver(gcm_connection_observer_.get());
-  driver_->Shutdown();
+  ShutdownDriver();
   driver_.reset();
   PumpIOLoop();
 
@@ -229,6 +237,7 @@ void GCMDriverTest::CreateDriver(
           base::MessageLoopProxy::current(),
           io_thread_.message_loop_proxy())).Pass(),
       GCMClient::ChromeBuildInfo(),
+      &prefs_,
       temp_dir_.path(),
       request_context,
       base::MessageLoopProxy::current(),
@@ -241,6 +250,12 @@ void GCMDriverTest::CreateDriver(
   driver_->AddConnectionObserver(gcm_connection_observer_.get());
 }
 
+void GCMDriverTest::ShutdownDriver() {
+  if (gcm_connection_observer())
+    driver()->RemoveConnectionObserver(gcm_connection_observer());
+  driver()->Shutdown();
+}
+
 void GCMDriverTest::AddAppHandlers() {
   driver_->AddAppHandler(kTestAppID1, gcm_app_handler_.get());
   driver_->AddAppHandler(kTestAppID2, gcm_app_handler_.get());
@@ -386,7 +401,7 @@ TEST_F(GCMDriverTest, Shutdown) {
   AddAppHandlers();
   EXPECT_TRUE(HasAppHandlers());
 
-  driver()->Shutdown();
+  ShutdownDriver();
   EXPECT_FALSE(HasAppHandlers());
   EXPECT_FALSE(driver()->IsConnected());
   EXPECT_FALSE(gcm_connection_observer()->connected());
@@ -941,4 +956,247 @@ TEST_F(GCMDriverFunctionalTest, MessagesDeleted) {
   EXPECT_EQ(kTestAppID1, gcm_app_handler()->app_id());
 }
 
+// Tests a single instance of GCMDriver.
+class GCMChannelStatusSyncerTest : public GCMDriverTest {
+ public:
+  GCMChannelStatusSyncerTest();
+  virtual ~GCMChannelStatusSyncerTest();
+
+  // testing::Test:
+  virtual void SetUp() OVERRIDE;
+
+  void CompleteGCMChannelStatusRequest(bool enabled, int poll_interval_seconds);
+  bool CompareDelaySeconds(bool expected_delay_seconds,
+                           bool actual_delay_seconds);
+
+  GCMChannelStatusSyncer* syncer() {
+    return driver()->gcm_channel_status_syncer_for_testing();
+  }
+
+ private:
+  net::TestURLFetcherFactory url_fetcher_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(GCMChannelStatusSyncerTest);
+};
+
+GCMChannelStatusSyncerTest::GCMChannelStatusSyncerTest() {
+}
+
+GCMChannelStatusSyncerTest::~GCMChannelStatusSyncerTest() {
+}
+
+void GCMChannelStatusSyncerTest::SetUp() {
+  GCMDriverTest::SetUp();
+
+  // Turn on all-user support.
+  ASSERT_TRUE(base::FieldTrialList::CreateFieldTrial("GCM", "Enabled"));
+}
+
+void GCMChannelStatusSyncerTest::CompleteGCMChannelStatusRequest(
+    bool enabled, int poll_interval_seconds) {
+  gcm_proto::ExperimentStatusResponse response_proto;
+  response_proto.mutable_gcm_channel()->set_enabled(enabled);
+
+  if (poll_interval_seconds)
+    response_proto.set_poll_interval_seconds(poll_interval_seconds);
+
+  std::string response_string;
+  response_proto.SerializeToString(&response_string);
+
+  net::TestURLFetcher* fetcher = url_fetcher_factory_.GetFetcherByID(0);
+  ASSERT_TRUE(fetcher);
+  fetcher->set_response_code(net::HTTP_OK);
+  fetcher->SetResponseString(response_string);
+  fetcher->delegate()->OnURLFetchComplete(fetcher);
+}
+
+bool GCMChannelStatusSyncerTest::CompareDelaySeconds(
+    bool expected_delay_seconds, bool actual_delay_seconds) {
+  // Most of time, the actual delay should not be smaller than the expected
+  // delay.
+  if (actual_delay_seconds >= expected_delay_seconds)
+    return true;
+  // It is also OK that the actual delay is a bit smaller than the expected
+  // delay in case that the test runs slowly.
+  return expected_delay_seconds - actual_delay_seconds < 30;
+}
+
+TEST_F(GCMChannelStatusSyncerTest, DisableAndEnable) {
+  // Create GCMDriver first. GCM is not started.
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+  EXPECT_FALSE(driver()->IsStarted());
+
+  // By default, GCM is enabled.
+  EXPECT_TRUE(driver()->gcm_enabled());
+  EXPECT_TRUE(syncer()->gcm_enabled());
+
+  // Remove delay such that the request could be executed immediately.
+  syncer()->set_delay_removed_for_testing(true);
+
+  // GCM will be started after app handler is added.
+  AddAppHandlers();
+  EXPECT_TRUE(driver()->IsStarted());
+
+  // GCM is still enabled at this point.
+  EXPECT_TRUE(driver()->gcm_enabled());
+  EXPECT_TRUE(syncer()->gcm_enabled());
+
+  // Wait until the GCM channel status request gets triggered.
+  PumpUILoop();
+
+  // Complete the request that disables the GCM.
+  CompleteGCMChannelStatusRequest(false, 0);
+  EXPECT_FALSE(driver()->gcm_enabled());
+  EXPECT_FALSE(syncer()->gcm_enabled());
+  EXPECT_FALSE(driver()->IsStarted());
+
+  // Wait until next GCM channel status request gets triggered.
+  PumpUILoop();
+
+  // Complete the request that enables the GCM.
+  CompleteGCMChannelStatusRequest(true, 0);
+  EXPECT_TRUE(driver()->gcm_enabled());
+  EXPECT_TRUE(syncer()->gcm_enabled());
+  EXPECT_TRUE(driver()->IsStarted());
+}
+
+TEST_F(GCMChannelStatusSyncerTest, DisableAndRestart) {
+  // Create GCMDriver first. GCM is not started.
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+  EXPECT_FALSE(driver()->IsStarted());
+
+  // By default, GCM is enabled.
+  EXPECT_TRUE(driver()->gcm_enabled());
+  EXPECT_TRUE(syncer()->gcm_enabled());
+
+  // Remove delay such that the request could be executed immediately.
+  syncer()->set_delay_removed_for_testing(true);
+
+  // GCM will be started after app handler is added.
+  AddAppHandlers();
+  EXPECT_TRUE(driver()->IsStarted());
+
+  // GCM is still enabled at this point.
+  EXPECT_TRUE(driver()->gcm_enabled());
+  EXPECT_TRUE(syncer()->gcm_enabled());
+
+  // Wait until the GCM channel status request gets triggered.
+  PumpUILoop();
+
+  // Complete the request that disables the GCM.
+  CompleteGCMChannelStatusRequest(false, 0);
+  EXPECT_FALSE(driver()->gcm_enabled());
+  EXPECT_FALSE(syncer()->gcm_enabled());
+  EXPECT_FALSE(driver()->IsStarted());
+
+  // Simulate browser start by recreating GCMDriver.
+  ShutdownDriver();
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+
+  // GCM is still disabled.
+  EXPECT_FALSE(driver()->gcm_enabled());
+  EXPECT_FALSE(syncer()->gcm_enabled());
+  EXPECT_FALSE(driver()->IsStarted());
+
+  AddAppHandlers();
+  EXPECT_FALSE(driver()->gcm_enabled());
+  EXPECT_FALSE(syncer()->gcm_enabled());
+  EXPECT_FALSE(driver()->IsStarted());
+}
+
+TEST_F(GCMChannelStatusSyncerTest, FirstTimePolling) {
+  // Start GCM.
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+  AddAppHandlers();
+
+  // The 1st request should be triggered shortly without jittering.
+  EXPECT_EQ(GCMChannelStatusSyncer::first_time_delay_seconds(),
+            syncer()->current_request_delay_interval().InSeconds());
+}
+
+TEST_F(GCMChannelStatusSyncerTest, SubsequentPollingWithDefaultInterval) {
+  // Create GCMDriver first. GCM is not started.
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+
+  // Remove delay such that the request could be executed immediately.
+  syncer()->set_delay_removed_for_testing(true);
+
+  // Now GCM is started.
+  AddAppHandlers();
+
+  // Wait until the GCM channel status request gets triggered.
+  PumpUILoop();
+
+  // Keep delay such that we can find out the computed delay time.
+  syncer()->set_delay_removed_for_testing(false);
+
+  // Complete the request. The default interval is intact.
+  CompleteGCMChannelStatusRequest(true, 0);
+
+  // The next request should be scheduled at the expected default interval.
+  int64 actual_delay_seconds =
+      syncer()->current_request_delay_interval().InSeconds();
+  int64 expected_delay_seconds =
+      GCMChannelStatusRequest::default_poll_interval_seconds();
+  EXPECT_TRUE(CompareDelaySeconds(expected_delay_seconds, actual_delay_seconds))
+      << "expected delay: " << expected_delay_seconds
+      << " actual delay: " << actual_delay_seconds;
+
+  // Simulate browser start by recreating GCMDriver.
+  ShutdownDriver();
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+  AddAppHandlers();
+
+  // After start-up, the request should still be scheduled at the expected
+  // default interval.
+  actual_delay_seconds =
+      syncer()->current_request_delay_interval().InSeconds();
+  EXPECT_TRUE(CompareDelaySeconds(expected_delay_seconds, actual_delay_seconds))
+      << "expected delay: " << expected_delay_seconds
+      << " actual delay: " << actual_delay_seconds;
+}
+
+TEST_F(GCMChannelStatusSyncerTest, SubsequentPollingWithUpdatedInterval) {
+  // Create GCMDriver first. GCM is not started.
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+
+  // Remove delay such that the request could be executed immediately.
+  syncer()->set_delay_removed_for_testing(true);
+
+  // Now GCM is started.
+  AddAppHandlers();
+
+  // Wait until the GCM channel status request gets triggered.
+  PumpUILoop();
+
+  // Keep delay such that we can find out the computed delay time.
+  syncer()->set_delay_removed_for_testing(false);
+
+  // Complete the request. The interval is being changed.
+  int new_poll_interval_seconds =
+      GCMChannelStatusRequest::default_poll_interval_seconds() * 2;
+  CompleteGCMChannelStatusRequest(true, new_poll_interval_seconds);
+
+  // The next request should be scheduled at the expected updated interval.
+  int64 actual_delay_seconds =
+      syncer()->current_request_delay_interval().InSeconds();
+  int64 expected_delay_seconds = new_poll_interval_seconds;
+  EXPECT_TRUE(CompareDelaySeconds(expected_delay_seconds, actual_delay_seconds))
+      << "expected delay: " << expected_delay_seconds
+      << " actual delay: " << actual_delay_seconds;
+
+  // Simulate browser start by recreating GCMDriver.
+  ShutdownDriver();
+  CreateDriver(FakeGCMClient::NO_DELAY_START);
+  AddAppHandlers();
+
+  // After start-up, the request should still be scheduled at the expected
+  // updated interval.
+  actual_delay_seconds =
+      syncer()->current_request_delay_interval().InSeconds();
+  EXPECT_TRUE(CompareDelaySeconds(expected_delay_seconds, actual_delay_seconds))
+      << "expected delay: " << expected_delay_seconds
+      << " actual delay: " << actual_delay_seconds;
+}
+
 }  // namespace gcm