[Sync] Move sessions/ to engine/cycle/ and rename things to match.

components/sync/sessions_impl/sync_session.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.
-
-// A class representing an attempt to synchronize the local syncable data
-// store with a sync server. A SyncSession instance is passed as a stateful
-// bundle throughout the sync cycle.  The SyncSession is not reused across
-// sync cycles; each cycle starts with a new one.
-
-#ifndef COMPONENTS_SYNC_SESSIONS_IMPL_SYNC_SESSION_H_
-#define COMPONENTS_SYNC_SESSIONS_IMPL_SYNC_SESSION_H_
-
-#include <map>
-#include <memory>
-#include <set>
-#include <string>
-#include <utility>
-#include <vector>
-
-#include "base/macros.h"
-#include "base/time/time.h"
-#include "components/sync/base/model_type.h"
-#include "components/sync/engine/model_safe_worker.h"
-#include "components/sync/engine_impl/sync_cycle_event.h"
-#include "components/sync/protocol/sync_protocol_error.h"
-#include "components/sync/sessions/sync_session_snapshot.h"
-#include "components/sync/sessions_impl/status_controller.h"
-#include "components/sync/sessions_impl/sync_session_context.h"
-
-namespace syncer {
-class ModelSafeWorker;
-class ProtocolEvent;
-
-namespace sessions {
-
-class NudgeTracker;
-
-class SyncSession {
- public:
-  // The Delegate services events that occur during the session requiring an
-  // explicit (and session-global) action, as opposed to events that are simply
-  // recorded in per-session state.
-  class Delegate {
-   public:
-    // The client was throttled and should cease-and-desist syncing activity
-    // until the specified time.
-    virtual void OnThrottled(const base::TimeDelta& throttle_duration) = 0;
-
-    // Some of the client's types were throttled.
-    virtual void OnTypesThrottled(ModelTypeSet types,
-                                  const base::TimeDelta& throttle_duration) = 0;
-
-    // Silenced intervals can be out of phase with individual sessions, so the
-    // delegate is the only thing that can give an authoritative answer for
-    // "is syncing silenced right now". This shouldn't be necessary very often
-    // as the delegate ensures no session is started if syncing is silenced.
-    // ** Note **  This will return true if silencing commenced during this
-    // session and the interval has not yet elapsed, but the contract here is
-    // solely based on absolute time values. So, this cannot be used to infer
-    // that any given session _instance_ is silenced.  An example of reasonable
-    // use is for UI reporting.
-    virtual bool IsCurrentlyThrottled() = 0;
-
-    // The client has been instructed to change its short poll interval.
-    virtual void OnReceivedShortPollIntervalUpdate(
-        const base::TimeDelta& new_interval) = 0;
-
-    // The client has been instructed to change its long poll interval.
-    virtual void OnReceivedLongPollIntervalUpdate(
-        const base::TimeDelta& new_interval) = 0;
-
-    // The client has been instructed to change a nudge delay.
-    virtual void OnReceivedCustomNudgeDelays(
-        const std::map<ModelType, base::TimeDelta>& nudge_delays) = 0;
-
-    // Called for the syncer to respond to the error sent by the server.
-    virtual void OnSyncProtocolError(
-        const SyncProtocolError& sync_protocol_error) = 0;
-
-    // Called when the server wants to change the number of hints the client
-    // will buffer locally.
-    virtual void OnReceivedClientInvalidationHintBufferSize(int size) = 0;
-
-    // Called when server wants to schedule a retry GU.
-    virtual void OnReceivedGuRetryDelay(const base::TimeDelta& delay) = 0;
-
-    // Called when server requests a migration.
-    virtual void OnReceivedMigrationRequest(ModelTypeSet types) = 0;
-
-   protected:
-    virtual ~Delegate() {}
-  };
-
-  // Build a session without a nudge tracker.  Used for poll or configure type
-  // sync cycles.
-  static SyncSession* Build(SyncSessionContext* context, Delegate* delegate);
-  ~SyncSession();
-
-  // Builds a thread-safe and read-only copy of the current session state.
-  SyncSessionSnapshot TakeSnapshot() const;
-  SyncSessionSnapshot TakeSnapshotWithSource(
-      sync_pb::GetUpdatesCallerInfo::GetUpdatesSource legacy_updates_source)
-      const;
-
-  // Builds and sends a snapshot to the session context's listeners.
-  void SendSyncCycleEndEventNotification(
-      sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source);
-  void SendEventNotification(SyncCycleEvent::EventCause cause);
-
-  void SendProtocolEvent(const ProtocolEvent& event);
-
-  // TODO(akalin): Split this into context() and mutable_context().
-  SyncSessionContext* context() const { return context_; }
-  Delegate* delegate() const { return delegate_; }
-  const StatusController& status_controller() const {
-    return *status_controller_.get();
-  }
-  StatusController* mutable_status_controller() {
-    return status_controller_.get();
-  }
-
- private:
-  SyncSession(SyncSessionContext* context, Delegate* delegate);
-
-  // The context for this session, guaranteed to outlive |this|.
-  SyncSessionContext* const context_;
-
-  // The delegate for this session, must never be NULL.
-  Delegate* const delegate_;
-
-  // Our controller for various status and error counters.
-  std::unique_ptr<StatusController> status_controller_;
-
-  DISALLOW_COPY_AND_ASSIGN(SyncSession);
-};
-
-}  // namespace sessions
-}  // namespace syncer
-
-#endif  // COMPONENTS_SYNC_SESSIONS_IMPL_SYNC_SESSION_H_