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

components/sync/engine_impl/clear_server_data.h

 // Copyright 2015 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_SYNC_ENGINE_IMPL_CLEAR_SERVER_DATA_H_
 #define COMPONENTS_SYNC_ENGINE_IMPL_CLEAR_SERVER_DATA_H_
 
 #include <string>
 
 #include "components/sync/base/syncer_error.h"
 #include "components/sync/protocol/sync.pb.h"
 
 namespace syncer {
 
-namespace sessions {
-class SyncSession;
-}
+class SyncCycle;
 
 // A ClearServerData operation.
 //
 // An instance of this class corresponds to a single operation and is
 // responsible for building a request, sending it, and interpreting the
 // response.
 class ClearServerData {
  public:
   explicit ClearServerData(const std::string& account_name);
   ~ClearServerData();
 
   // Sends the request, blocking until the request has completed.
-  SyncerError SendRequest(sessions::SyncSession* session);
+  SyncerError SendRequest(SyncCycle* cycle);
 
  private:
   sync_pb::ClientToServerMessage request_;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_IMPL_CLEAR_SERVER_DATA_H_