sync: Introduce classes for per-type counters

sync/internal_api/public/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 "sync/internal_api/public/sessions/status_counters.h"
+
+#include "base/json/json_string_value_serializer.h"
+#include "base/values.h"
+
+namespace syncer {
+
+StatusCounters::StatusCounters()
+  : num_total_entries(0) {}
+
+StatusCounters::~StatusCounters() {}
+
+scoped_ptr<base::DictionaryValue> StatusCounters::ToValue() const {
+  scoped_ptr<base::DictionaryValue> value(new base::DictionaryValue());
+  value->SetInteger("numTotalEntries", num_total_entries);
+  return value.Pass();
+}
+
+std::string StatusCounters::ToString() const {
+  std::string result;
+  scoped_ptr<base::DictionaryValue> value = ToValue();
+  JSONStringValueSerializer serializer(&result);
+  serializer.Serialize(*value);
+  return result;
+}
+
+}  // namespace syncer