Adding support for pre-sent messages

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;
   }
 
+  ValueType* GetMutableValue(const KeyType& key) {
+    ClearExpiredTokens();
+    return &map_[key];

[rkc, 2015/01/07 23:06:10]

If the element doesn't exist, this will actually add the key to the map. Use
find first to confirm that the key does exist; otherwise return nullptr.

[Charlie, 2015/01/08 16:47:34]

That's more consistent with the rest of the API - but I don't think it's a good
API. Added a TODO to discuss later.

Done.

+  }
+
+  size_t Erase(const KeyType& key) {

[rkc, 2015/01/07 23:06:10]

Add a TODO to add a unit test to test this.

[Charlie, 2015/01/08 16:47:34]

Done.

+    return map_.erase(key);
+  }
+
   void set_clock_for_testing(scoped_ptr<base::TickClock> clock) {
     clock_ = clock.Pass();
   }
 
  private:
   void ClearExpiredTokens() {
     while (!expiry_queue_.empty() &&
            expiry_queue_.top().second <= clock_->NowTicks())
       ClearOldestToken();
   }
@@ skipping 26 matching lines @@
   // 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_