Change base::TickClock to a ref counted class.

components/copresence/timed_map.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_TIMED_MAP_H_
 #define COMPONENTS_COPRESENCE_TIMED_MAP_H_
 
 #include <map>
 #include <queue>
 #include <utility>
@@ skipping 34 matching lines @@
     ClearExpiredTokens();
     return map_.find(key) != map_.end();
   }
 
   const ValueType& GetValue(const KeyType& key) {
     ClearExpiredTokens();
     auto elt = map_.find(key);
     return elt == map_.end() ? kEmptyValue : elt->second;
   }
 
-  void set_clock_for_testing(scoped_ptr<base::TickClock> clock) {
-    clock_ = clock.Pass();
+  void set_clock_for_testing(const scoped_refptr<base::TickClock>& clock) {
+    clock_ = clock;
   }
 
  private:
   void ClearExpiredTokens() {
     while (!expiry_queue_.empty() &&
            expiry_queue_.top().second <= clock_->NowTicks())
       ClearOldestToken();
   }
 
   void ClearOldestToken() {
     map_.erase(expiry_queue_.top().first);
     expiry_queue_.pop();
   }
 
   typedef std::pair<KeyType, base::TimeTicks> KeyTimeTuple;
 
   class EarliestFirstComparator {
    public:
     // This will sort our queue with the 'earliest' time being the top.
     bool operator()(const KeyTimeTuple& left, const KeyTimeTuple& right) const {
       return left.second > right.second;
     }
   };
 
   typedef std::priority_queue<KeyTimeTuple, std::vector<KeyTimeTuple>,
                               EarliestFirstComparator> ExpiryQueue;
 
   const ValueType kEmptyValue;
 
-  scoped_ptr<base::TickClock> clock_;
+  scoped_refptr<base::TickClock> clock_;
   base::RepeatingTimer<TimedMap> timer_;
   const base::TimeDelta lifetime_;
   const size_t max_elements_;
   std::map<KeyType, ValueType> map_;
   // Priority queue with our element keys ordered by the earliest expiring keys
   // first.
   ExpiryQueue expiry_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(TimedMap);
 };
 
 }  // namespace copresence
 
 #endif  // COMPONENTS_COPRESENCE_TIMED_MAP_H_