Redesign the copresence audio handlers.

components/copresence/handlers/audio/audio_directive_list.h

 // 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.
 
 #ifndef COMPONENTS_COPRESENCE_HANDLERS_AUDIO_AUDIO_DIRECTIVE_LIST_H_
 #define COMPONENTS_COPRESENCE_HANDLERS_AUDIO_AUDIO_DIRECTIVE_LIST_H_
 
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 
+namespace base {
+class TickClock;
+}
+
 namespace media {
 class AudioBusRefCounted;
 }
 
 namespace copresence {
 
-struct AudioDirective {
+struct AudioDirective final {
   // Default ctor, required by the priority queue.
   AudioDirective();
-  AudioDirective(const std::string& op_id, base::Time end_time);
+  AudioDirective(const std::string& op_id, base::TimeTicks end_time);
 
   std::string op_id;
-  base::Time end_time;
+  base::TimeTicks end_time;
 };
 
 // This class maintains a list of active audio directives. It fetches the audio
 // samples associated with a audio transmit directives and expires directives
 // that have outlived their TTL.
 // TODO(rkc): Once we implement more token technologies, move reusable code
 // from here to a base class and inherit various XxxxDirectiveList
 // classes from it.
 class AudioDirectiveList {
  public:
   AudioDirectiveList();
-  virtual ~AudioDirectiveList();
+  ~AudioDirectiveList();
 
   void AddDirective(const std::string& op_id, base::TimeDelta ttl);
   void RemoveDirective(const std::string& op_id);
 
   scoped_ptr<AudioDirective> GetActiveDirective();
 
  private:
   // Comparator for comparing end_times on audio tokens.
   class LatestFirstComparator {
    public:
     // This will sort our queue with the 'latest' time being the top.
     bool operator()(const AudioDirective& left,
                     const AudioDirective& right) const {
       return left.end_time < right.end_time;
     }
   };
 
   std::vector<AudioDirective>::iterator FindDirectiveByOpId(
       const std::string& op_id);
 
   // This vector will be organized as a heap with the latest time as the first
   // element. Only currently active directives will exist in this list.
   std::vector<AudioDirective> active_directives_;
 
+  scoped_ptr<base::TickClock> clock_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioDirectiveList);
 };
 
 }  // namespace copresence
 
 #endif  // COMPONENTS_COPRESENCE_HANDLERS_AUDIO_AUDIO_DIRECTIVE_LIST_H_