Add BytesRead metric to CPM

chrome/browser/performance_monitor/metric.h

 // 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.
 
 #ifndef CHROME_BROWSER_PERFORMANCE_MONITOR_METRIC_H_
 #define CHROME_BROWSER_PERFORMANCE_MONITOR_METRIC_H_
 
 #include <string>
 #include "base/time.h"
 
 namespace performance_monitor {
 
 // IMPORTANT: This is used as an indication of the metric type within the
 // performance monitor database; do not change the order! If you add new
 // metric types to this list, place them above METRIC_NUMBER_OF_METRICS and add
 // the appropriate constants to metric_details.
 enum MetricType {
 METRIC_CPU_USAGE,
 METRIC_PRIVATE_MEMORY_USAGE,
 METRIC_SHARED_MEMORY_USAGE,
 METRIC_STARTUP_TIME,
 METRIC_TEST_STARTUP_TIME,
 METRIC_SESSION_RESTORE_TIME,
 METRIC_PAGE_LOAD_TIME,
+METRIC_NETWORK_BYTES_READ,
 METRIC_NUMBER_OF_METRICS
 };
 
 struct Metric {
  public:
   Metric();
   Metric(const base::Time& metric_time, const double metric_value);
   Metric(const std::string& metric_time, const std::string& metric_value);
   ~Metric();
 
   base::Time time;
   double value;
 };
 
 }  // namespace performance_monitor
 
 #endif  // CHROME_BROWSER_PERFORMANCE_MONITOR_METRIC_H_