[Sync] Move //sync to //components/sync.

sync/engine/backoff_delay_provider.h

-// Copyright 2012 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 SYNC_ENGINE_BACKOFF_DELAY_PROVIDER_H_
-#define SYNC_ENGINE_BACKOFF_DELAY_PROVIDER_H_
-
-#include "base/macros.h"
-#include "base/time/time.h"
-#include "sync/base/sync_export.h"
-
-namespace syncer {
-
-namespace sessions {
-struct ModelNeutralState;
-}
-
-// A component used to get time delays associated with exponential backoff.
-class SYNC_EXPORT BackoffDelayProvider {
- public:
-  // Factory function to create a standard BackoffDelayProvider.
-  static BackoffDelayProvider* FromDefaults();
-
-  // Similar to above, but causes sync to retry very quickly (see
-  // polling_constants.h) when it encounters an error before exponential
-  // backoff.
-  //
-  // *** NOTE *** This should only be used if kSyncShortInitialRetryOverride
-  // was passed to command line.
-  static BackoffDelayProvider* WithShortInitialRetryOverride();
-
-  virtual ~BackoffDelayProvider();
-
-  // DDOS avoidance function.  Calculates how long we should wait before trying
-  // again after a failed sync attempt, where the last delay was |base_delay|.
-  // TODO(tim): Look at URLRequestThrottlerEntryInterface.
-  virtual base::TimeDelta GetDelay(const base::TimeDelta& last_delay);
-
-  // Helper to calculate the initial value for exponential backoff.
-  // See possible values and comments in polling_constants.h.
-  virtual base::TimeDelta GetInitialDelay(
-      const sessions::ModelNeutralState& state) const;
-
- protected:
-  BackoffDelayProvider(const base::TimeDelta& default_initial_backoff,
-                       const base::TimeDelta& short_initial_backoff);
-
- private:
-  const base::TimeDelta default_initial_backoff_;
-  const base::TimeDelta short_initial_backoff_;
-
-  DISALLOW_COPY_AND_ASSIGN(BackoffDelayProvider);
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_ENGINE_BACKOFF_DELAY_PROVIDER_H_