Enable cpplint for webrtc/modules/pacing and fix all uncovered cpplint errors.

webrtc/modules/pacing/packet_router.cc

Index: webrtc/modules/pacing/packet_router.cc
diff --git a/webrtc/modules/pacing/packet_router.cc b/webrtc/modules/pacing/packet_router.cc
index e98ab0c2b02539963758ce0259c412e5657f385f..ac75d2cd4a65c6fe9a033ba6322bc10b1863a4d9 100644
--- a/webrtc/modules/pacing/packet_router.cc
+++ b/webrtc/modules/pacing/packet_router.cc
@@ -40,7 +40,7 @@ bool SendFeedback(rtcp::TransportFeedback* packet,
   }
   return false;
 }
-}
+}  // namespace
 
 PacketRouter::PacketRouter() : transport_seq_(0) {
   pacer_thread_checker_.DetachFromThread();