Notify NQE of TCP RTT values

net/base/socket_performance_watcher.h

 // Copyright 2015 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_SOCKET_PERFORMANCE_WATCHER_H_
 #define NET_BASE_SOCKET_PERFORMANCE_WATCHER_H_
 
+#include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "net/base/net_export.h"
 #include "net/base/socket_performance_watcher_factory.h"
 
 namespace base {
 class TimeDelta;
 }  // namespace base
 
 namespace net {
 
 // SocketPerformanceWatcher is the base class for recording and aggregating
 // socket statistics.
 class NET_EXPORT_PRIVATE SocketPerformanceWatcher {
  public:
   // |socket_performance_watcher_factory| is the factory that constructed
   // |this| watcher.
   SocketPerformanceWatcher(
       const SocketPerformanceWatcherFactory::Protocol protocol,
       SocketPerformanceWatcherFactory* socket_performance_watcher_factory);
 
   virtual ~SocketPerformanceWatcher();
 
   // Called when updated transport layer RTT information is available. This
   // must be the transport layer RTT from this device to the remote transport
   // layer endpoint. This method is called immediately after the observation is
   // made, hence no timestamp.
-  void OnUpdatedRTTAvailable(const base::TimeDelta& rtt) const;
+  void OnUpdatedRTTAvailable(const base::TimeDelta& rtt);
+
+  // Returns true if |this| can be notified of a new RTT value.

[Ryan Sleevi, 2016/03/02 19:56:57]

I'm not sure what this means?

[tbansal1, 2016/03/03 02:09:08]

I renamed the function name, and edited the comment to make it clearer.

+  bool CanNotifyRTT() const WARN_UNUSED_RESULT;
+
+  // Called when |this| socket performance watcher is reused for establishing a
+  // new transport layer connection.

[Ryan Sleevi, 2016/03/02 19:56:57]

https://google.github.io/styleguide/cppguide.html#Function_Comments

You should define the operation, not the use

// Resets the internal state of this SocketPerformanceWatcher in
// preparation for observing a new socket.
// Note: The new socket MUST share the same protocol as the previously
// observed socket.

[tbansal1, 2016/03/03 02:09:08]

Done.

+  void Reset() const;
 
  private:
   // Transport layer protocol used by the socket that |this| is watching.
   const SocketPerformanceWatcherFactory::Protocol protocol_;
 
+  // Time when the last RTT notification was received.
+  base::TimeTicks last_rtt_notification_;
+
+  // Minimum time interval between two successive OnUpdatedRTTAvailable
+  // notifications to |this|.
+  const base::TimeDelta rtt_notification_interval_;
+
   // |socket_performance_watcher_factory_| is the factory that created
   // |this| watcher.
   SocketPerformanceWatcherFactory* socket_performance_watcher_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SocketPerformanceWatcher);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_SOCKET_PERFORMANCE_WATCHER_H_