Support needed to measure user and service traffic in Chrome.

chrome/browser/net/data_use_user_data.cc

+// Copyright (c) 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.
+
+#include <string>
+
+#include "chrome/browser/net/data_use_user_data.h"
+
+DataUseUserData::DataUseUserData(std::string service_name)
+    : service_name_(service_name) {}
+
+DataUseUserData::~DataUseUserData() {}
+
+// static
+const void* DataUseUserData::kUserDataKey =
+    static_cast<const void*>(&DataUseUserData::kUserDataKey);
+
+// Helper function to create DataUseUserData.
+base::SupportsUserData::Data* CreateDataUseUserData(
+      std::string service_name) {
+    return new DataUseUserData(service_name);
+  }