Get rid of unqualified std:: types.

webrtc/modules/pacing/paced_sender.cc

Index: webrtc/modules/pacing/paced_sender.cc
diff --git a/webrtc/modules/pacing/paced_sender.cc b/webrtc/modules/pacing/paced_sender.cc
index b64e366d48f2ac0444955cbe8516d425610b99b2..91e3af0f1a1c7352759268dce4de86524e10a9d4 100644
--- a/webrtc/modules/pacing/paced_sender.cc
+++ b/webrtc/modules/pacing/paced_sender.cc
@@ -193,7 +193,7 @@ class PacketQueue {
   std::priority_queue<Packet*, std::vector<Packet*>, Comparator> prio_queue_;
   // Total number of bytes in the queue.
   uint64_t bytes_;
-  // Map<ssrc, set<seq_no> >, for checking duplicates.
+  // Map<ssrc, std::set<seq_no> >, for checking duplicates.
   typedef std::map<uint32_t, std::set<uint16_t> > SsrcSeqNoMap;
   SsrcSeqNoMap dupe_map_;
   Clock* const clock_;