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

components/sync/sessions/status_counters.cc

-// 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.
-
-#include "components/sync/sessions/status_counters.h"
-
-#include "base/json/json_string_value_serializer.h"
-#include "base/values.h"
-
-namespace syncer {
-
-StatusCounters::StatusCounters()
-    : num_entries(0), num_entries_and_tombstones(0) {}
-
-StatusCounters::~StatusCounters() {}
-
-std::unique_ptr<base::DictionaryValue> StatusCounters::ToValue() const {
-  std::unique_ptr<base::DictionaryValue> value(new base::DictionaryValue());
-  value->SetInteger("numEntries", num_entries);
-  value->SetInteger("numEntriesAndTombstones", num_entries_and_tombstones);
-  return value;
-}
-
-std::string StatusCounters::ToString() const {
-  std::string result;
-  std::unique_ptr<base::DictionaryValue> value = ToValue();
-  JSONStringValueSerializer serializer(&result);
-  serializer.Serialize(*value);
-  return result;
-}
-
-}  // namespace syncer