media: Use stl utilities from the base namespace

media/cdm/player_tracker_impl.cc

Index: media/cdm/player_tracker_impl.cc
diff --git a/media/cdm/player_tracker_impl.cc b/media/cdm/player_tracker_impl.cc
index 7d5cda3bd053c31ceef9b308c8e7166ad2c16dc2..e0caf7b87f756cd9e4e5f584fde21b675335d5c9 100644
--- a/media/cdm/player_tracker_impl.cc
+++ b/media/cdm/player_tracker_impl.cc
@@ -30,7 +30,7 @@ int PlayerTrackerImpl::RegisterPlayer(const base::Closure& new_key_cb,
                                       const base::Closure& cdm_unset_cb) {
   base::AutoLock lock(lock_);
   int registration_id = next_registration_id_++;
-  DCHECK(!ContainsKey(player_callbacks_map_, registration_id));
+  DCHECK(!base::ContainsKey(player_callbacks_map_, registration_id));
   player_callbacks_map_.insert(std::make_pair(
       registration_id, PlayerCallbacks(new_key_cb, cdm_unset_cb)));
   return registration_id;
@@ -38,7 +38,7 @@ int PlayerTrackerImpl::RegisterPlayer(const base::Closure& new_key_cb,
 
 void PlayerTrackerImpl::UnregisterPlayer(int registration_id) {
   base::AutoLock lock(lock_);
-  DCHECK(ContainsKey(player_callbacks_map_, registration_id))
+  DCHECK(base::ContainsKey(player_callbacks_map_, registration_id))
       << registration_id;
   player_callbacks_map_.erase(registration_id);
 }