Add a new NetworkActivityMonitor to track network activity

net/base/network_activity_monitor.h

Index: net/base/network_activity_monitor.h
diff --git a/net/base/network_activity_monitor.h b/net/base/network_activity_monitor.h
new file mode 100644
index 0000000000000000000000000000000000000000..98ad189146c0f221c6cdea994cdd6c1af29fa158
--- /dev/null
+++ b/net/base/network_activity_monitor.h
@@ -0,0 +1,68 @@
+// Copyright (c) 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.
+
+#ifndef NET_BASE_NETWORK_ACTIVITY_MONITOR_H_
+#define NET_BASE_NETWORK_ACTIVITY_MONITOR_H_
+
+#include "base/basictypes.h"
+#include "base/lazy_instance.h"
+#include "base/synchronization/lock.h"
+#include "base/time/time.h"
+#include "net/base/net_export.h"
+
+namespace net {
+
+namespace test {
+
+class NetworkActivityMonitorPeer;
+
+}  // namespace test
+
+// NetworkActivityMonitor tracks network activity across all sockets and
+// provides cumulative statistics about bytes sent to and received from
+// the network. It uses locks to ensure thread-safety.

[eroman, 2014/11/14 20:57:04]

nit: locks --> "a lock" or alternately "locking"

[Ryan Hamilton, 2014/11/14 22:18:17]

Done.

+//
+// There are a few caveats:
+//  * Bytes "sent" includes all bytes all send attempts and may include

[eroman, 2014/11/14 20:57:04]

"all bytes all send attempts" --> reword

[Ryan Hamilton, 2014/11/14 22:18:17]

Done.

+//    some bytes which were actually never sent over the network.
+//  * Bytes received includes only bytes actually received from the network,
+//    and does not include any bytes read from the the cache.
+//  * Network activity not initiated directly using chromium sockets won't
+//    be reflected here (for instance DNS queries issued by getaddrinfo()).
+class NET_EXPORT_PRIVATE NetworkActivityMonitor {
+ public:
+  // Returns the singleton instance of the monitor.
+  static NetworkActivityMonitor* GetInstance();
+
+  void IncrementBytesReceived(uint64_t bytes_received);
+  void IncrementBytesSent(uint64_t bytes_sent);
+
+  uint64_t GetBytesReceived() const;
+  uint64_t GetBytesSent() const;
+
+  base::TimeDelta GetTimeSinceLastReceived() const;
+  base::TimeDelta GetTimeSinceLastSent() const;
+
+ private:
+  friend class test::NetworkActivityMonitorPeer;
+
+  NetworkActivityMonitor();
+  ~NetworkActivityMonitor();
+  friend struct base::DefaultLazyInstanceTraits<NetworkActivityMonitor>;
+
+  // Protects all the following members.
+  mutable base::Lock lock_;
+
+  uint64_t bytes_received_;
+  uint64_t bytes_sent_;
+
+  base::TimeTicks last_received_ticks_;
+  base::TimeTicks last_write_ticks_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkActivityMonitor);
+};
+
+}  // namespace net
+
+#endif  // NET_BASE_NETWORK_ACTIVITY_MONITOR_H_