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

components/gcm_driver/gcm_channel_status_syncer.h

Index: components/gcm_driver/gcm_channel_status_syncer.h
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 0000000000000000000000000000000000000000..83cfbda30cbf3b500d890420880ecbad81610e67
--- /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_