Factor a scheduler object out of MetricsService.

chrome/browser/metrics/metrics_reporting_scheduler.h

+// Copyright (c) 2011 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_METRICS_METRICS_REPORTING_SCHEDULER_H_
+#define CHROME_BROWSER_METRICS_METRICS_REPORTING_SCHEDULER_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/task.h"
+
+class MetricsService;
+
+// Scheduler task to drive a MetricsService object's uploading.
+class MetricsReportingScheduler {
+ public:
+  explicit MetricsReportingScheduler(MetricsService* metrics_service);
+  virtual ~MetricsReportingScheduler();

[jar (doing other things), 2011/04/16 02:03:13]

Why the virtual destructor?  There is no base, and I didn't see tests that
derive from this class.

[stuartmorgan, 2011/04/18 17:03:00]

Just habit; removed.

+
+  // Starts scheduling uploads. This in a no-op if the scheduler is already
+  // running, so it is safe to call more than once.
+  void Start();
+
+  // Stops scheduling uploads.
+  void Stop();
+
+  // Callback from MetricsService when a triggered upload finishes.
+  void UploadFinished(bool server_is_healthy, bool more_logs_remaining);
+
+  // Callback from MetricsService when a triggered upload is cancelled by the
+  // MetricsService.
+  void UploadCancelled();
+
+ private:
+  // Timer callback indicating it's time for the MetricsService to upload
+  // metrics.
+  void TriggerUpload();
+
+  // Schedules a future call to TriggerUpload if one isn't already pending.
+  void ScheduleNextCallback();
+
+  // Increases the upload interval each time it's called, to handle the case
+  // where the server is having issues.
+  void BackOffUploadInterval();
+
+  // Weak reference to the MetricsService being scheduled.
+  MetricsService* metrics_service_;
+
+  ScopedRunnableMethodFactory<MetricsReportingScheduler> upload_timer_factory_;
+
+  // The interval between being told an upload is done and starting the next
+  // upload.
+  base::TimeDelta upload_interval_;
+
+  // Indicates that the scheduler is running (i.e., that Start has been called
+  // more recently than Stop).
+  bool running_;
+
+  // Indicates that a timer for triggering the next upload has already been
+  // started.
+  bool timer_pending_;
+
+  // Indicates that the last triggered upload hasn't resolved yet.
+  bool callback_pending_;
+
+  DISALLOW_COPY_AND_ASSIGN(MetricsReportingScheduler);
+};
+
+#endif  // CHROME_BROWSER_METRICS_METRICS_REPORTING_SCHEDULER_H_