Update ConnectionEventTracker to check if there is an in progress attempt.

google_apis/gcm/engine/connection_event_tracker.cc

 // 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.
 
 #include "google_apis/gcm/engine/connection_event_tracker.h"
 
 #include "base/time/time.h"
 #include "net/base/network_change_notifier.h"
 
 namespace {
@@ skipping 14 matching lines @@
   // TODO(harkness): Can we dcheck here that there is not an in progress
   // connection?
   current_event_.set_time_connection_started_ms(base::Time::Now().ToJavaTime());
   // The connection type is passed to the server and stored there, so the
   // values should remain consistent.
   current_event_.set_network_type(
       static_cast<int>(net::NetworkChangeNotifier::GetConnectionType()));
 }
 
 void ConnectionEventTracker::EndConnectionAttempt() {
-  // TODO(harkness): Modify tests so that we can put a DCHECK here.

[Peter Beverloo, 2017/01/11 14:31:48]

Why isn't the TODO relevant anymore?

-  if (completed_events_.size() == kMaxClientEvents) {
-    // Don't let the completed events grow beyond the max.
-    completed_events_.pop_front();
-    number_discarded_events_++;
+  // It is possible to get EndConnectionAttempt when there is not an in progress
+  // event, because EndConnectionAttempt is called from SignalConnectionReset,
+  // which will be called any time the network changes state. Only save the
+  // current_event_ if it has data.
+  if (current_event_.has_time_connection_started_ms()) {

[Peter Beverloo, 2017/01/11 14:31:48]

style nit: prefer early return over nesting.

  if (!current_event_.has_time_connection_started_ms())
    return;

[harkness, 2017/01/12 11:04:48]

No longer applicable.

+    if (completed_events_.size() == kMaxClientEvents) {
+      // Don't let the completed events grow beyond the max.
+      completed_events_.pop_front();
+      number_discarded_events_++;
+    }
+
+    // Current event is finished, so add it to our list of completed events.
+    current_event_.set_time_connection_ended_ms(base::Time::Now().ToJavaTime());
+    completed_events_.push_back(current_event_);
+    current_event_.Clear();
   }
-
-  // Current event is now completed, so add it to our list of completed events.
-  current_event_.set_time_connection_ended_ms(base::Time::Now().ToJavaTime());
-  completed_events_.push_back(current_event_);
-  current_event_.Clear();
 }
 
 void ConnectionEventTracker::ConnectionAttemptSucceeded() {
   // Record the successful connection so information about it can be sent in the
   // next login request. If there is a login failure, this will need to be
   // updated to a failed connection.
   current_event_.set_type(mcs_proto::ClientEvent::SUCCESSFUL_CONNECTION);
   current_event_.set_time_connection_established_ms(
       base::Time::Now().ToJavaTime());
 
@@ skipping 30 matching lines @@
     mcs_proto::ClientEvent* event = request->add_client_event();
     event->set_type(mcs_proto::ClientEvent::DISCARDED_EVENTS);
     event->set_number_discarded_events(number_discarded_events_);
   }
 
   for (const mcs_proto::ClientEvent& event : completed_events_)
     request->add_client_event()->CopyFrom(event);
 }
 
 }  // namespace gcm