Adding support for pre-sent messages

components/copresence/timed_map.h

Index: components/copresence/timed_map.h
diff --git a/components/copresence/timed_map.h b/components/copresence/timed_map.h
index 98e1517e73e92ac0c5a4bdff440386809637144d..2de553799e8586e5d3b693398ccef7840097da82 100644
--- a/components/copresence/timed_map.h
+++ b/components/copresence/timed_map.h
@@ -52,6 +52,15 @@ class TimedMap {
     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();
   }