Added ConnectionTimeObserver to calculate the times to authenticate and connect.

remoting/test/connection_time_observer.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 REMOTING_TEST_CONNECTION_TIME_OBSERVER_H_
+#define REMOTING_TEST_CONNECTION_TIME_OBSERVER_H_
+
+#include <map>
+
+#include "remoting/test/remote_connection_observer.h"
+
+namespace base {
+class TimeDelta;
+class Timer;
+}
+
+namespace remoting {
+namespace test {
+
+// Observes and saves the times when a chromoting client changes its state. It
+// allows for tests to access latency times between the different states the
+// client transitioned through.
+class ConnectionTimeObserver
+    : public RemoteConnectionObserver {
+ public:
+  explicit ConnectionTimeObserver(base::Timer* timer);
+  ~ConnectionTimeObserver() override;
+
+  // RemoteConnectionObserver interface.
+  void ConnectionStateChanged(protocol::ConnectionToHost::State state,
+                              protocol::ErrorCode error_code) override;
+  void ConnectionReady(bool ready) override;
+
+  // Initializes INITIALIZING state's TimeTicks.

[joedow, 2015/07/27 16:25:39]

This comment is awkward, I think the method name is a little hard to understand.
 The idea for the name depends on how your want people to use this class
(previously I mentioned a stopwatch as an example though I don't think that is
the usage here).  I mentioned in a previous iteration that you could use an
override for 'ConnectionStateChanged' which just took the state, that may still
be cleaner as I wouldn't know what this method did without reading the code.

[tonychun, 2015/07/27 21:20:42]

I've added clearer comments and changed the name to Initialize.

+  void SetInitializingState();
+
+  // Prints out connection performance stats to STDOUT.
+  void DisplayConnectionStats() const;
+
+  // Returns the time delta in milliseconds between |start_state| and
+  // |end_state| stored in |transition_times_map_|.
+  base::TimeDelta GetStateTransitionDelayTimeDelta(

[anandc, 2015/07/27 18:22:29]

GetStateTransitionTime.

[tonychun, 2015/07/27 21:20:42]

Done.

+      protocol::ConnectionToHost::State start_state,
+      protocol::ConnectionToHost::State end_state) const;
+
+  // Used to set fake state transition times for ConnectionTimeObserver tests.
+  void SetTransitionTimesMapForTest(
+      const std::map<protocol::ConnectionToHost::State, base::TimeTicks>& map);
+
+ private:
+  // Saves the current connection state of client to host.
+  protocol::ConnectionToHost::State current_connection_state_ =
+      protocol::ConnectionToHost::State::INITIALIZING;
+
+  // Stores TimeTick of states the client changes to.

[anandc, 2015/07/27 18:22:29]

"The TimeTicks to get to a state from the previous state."

[tonychun, 2015/07/27 21:20:42]

Done.

+  std::map<protocol::ConnectionToHost::State, base::TimeTicks>
+      transition_times_map_;
+
+  // Allows for observer to run timer's closure. ConnectionTimeObserver does not
+  // does not own the lifetime of the timer, so the timer should outlast the
+  // chromoting connection time and the ConnectionTimeObserver.
+  base::Timer* timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(ConnectionTimeObserver);
+};
+
+}  // namespace test
+}  // namespace remoting
+
+#endif  // REMOTING_TEST_CONNECTION_TIME_OBSERVER_H_