Fixing race condition in AudioDirectiveHandler

components/copresence/handlers/audio/audio_directive_handler_impl.cc

 // Copyright 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.
 
 #include "components/copresence/handlers/audio/audio_directive_handler_impl.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 12 matching lines @@
 using audio_modem::AUDIBLE;
 using audio_modem::INAUDIBLE;
 using audio_modem::TokenParameters;
 
 namespace copresence {
 
 namespace {
 
 base::TimeTicks GetEarliestEventTime(AudioDirectiveList* list,
                                      base::TimeTicks event_time) {
-  if (!list->GetActiveDirective())
+  scoped_ptr<AudioDirective> active_directive = list->GetActiveDirective();
+
+  if (!active_directive)
     return event_time;
+  if (event_time.is_null())
+    return active_directive->end_time;
 
-  return event_time.is_null() ?
-      list->GetActiveDirective()->end_time :
-      std::min(list->GetActiveDirective()->end_time, event_time);
+  return std::min(active_directive->end_time, event_time);
 }
 
 void ConvertDirectives(const std::vector<AudioDirective>& in_directives,
                        std::vector<Directive>* out_directives) {
   for (const AudioDirective& in_directive : in_directives)
     out_directives->push_back(in_directive.server_directive);
 }
 
 }  // namespace
 
@@ skipping 178 matching lines @@
 
   *expiry = GetEarliestEventTime(transmits_lists_[AUDIBLE], base::TimeTicks());
   *expiry = GetEarliestEventTime(transmits_lists_[INAUDIBLE], *expiry);
   *expiry = GetEarliestEventTime(receives_lists_[AUDIBLE], *expiry);
   *expiry = GetEarliestEventTime(receives_lists_[INAUDIBLE], *expiry);
 
   return !expiry->is_null();
 }
 
 }  // namespace copresence