Split SocketWatcher and SocketWatcherFactory out of NQE

net/nqe/socket_watcher.h

+// Copyright 2016 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_NQE_SOCKET_WATCHER_H_
+#define NET_NQE_SOCKET_WATCHER_H_
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "net/socket/socket_performance_watcher.h"
+#include "net/socket/socket_performance_watcher_factory.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+class TimeDelta;
+}  // namespace base
+
+namespace net {
+
+namespace {
+typedef base::Callback<void(SocketPerformanceWatcherFactory::Protocol protocol,
+                            const base::TimeDelta& rtt)>
+    OnUpdatedRTTAvailableCallback;
+}
+
+namespace nqe {
+
+namespace internal {
+
+// SocketWatcher implements SocketPerformanceWatcher, and calls
+// |updated_rtt_observation_callback| every time a new RTT observation is
+// available. SocketWatcher is not thread-safe.
+class SocketWatcher : public SocketPerformanceWatcher {
+ public:
+  SocketWatcher(SocketPerformanceWatcherFactory::Protocol protocol,

[bengr, 2016/06/01 17:41:04]

Please add a comment that describes the parameters. Also, somewhere explain what
runs on the task runner.

[tbansal1, 2016/06/01 18:24:36]

Done.

+                scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+                OnUpdatedRTTAvailableCallback updated_rtt_observation_callback);
+
+  ~SocketWatcher() override;
+
+  // SocketPerformanceWatcher implementation:
+  bool ShouldNotifyUpdatedRTT() const override;
+  void OnUpdatedRTTAvailable(const base::TimeDelta& rtt) override;
+  void OnConnectionChanged() override;
+
+ private:
+  // Transport layer protocol used by the socket that |this| is watching.
+  const SocketPerformanceWatcherFactory::Protocol protocol_;
+
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
+  // Called every time a new RTT observation is available.
+  OnUpdatedRTTAvailableCallback updated_rtt_observation_callback_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(SocketWatcher);
+};
+
+}  // namespace internal
+
+}  // namespace nqe
+
+}  // namespace net
+
+#endif  // NET_NQE_SOCKET_WATCHER_H_