[Sync] Store the past 10 traffic records in memory.

sync/engine/syncer_proto_util.cc

Index: sync/engine/syncer_proto_util.cc
diff --git a/sync/engine/syncer_proto_util.cc b/sync/engine/syncer_proto_util.cc
index b1ed209c7fc473c0400d1563d3262aedd51bc829..0378d414b22c4378f034eeb7cb20c1aee041f18c 100644
--- a/sync/engine/syncer_proto_util.cc
+++ b/sync/engine/syncer_proto_util.cc
@@ -338,7 +338,7 @@ SyncerError SyncerProtoUtil::PostClientToServerMessage(
 
   syncable::Directory* dir = session->context()->directory();
 
-  LogClientToServerMessage(msg);
+  LogClientToServerMessage(msg, session);
   if (!PostAndProcessHeaders(session->context()->connection_manager(), session,
                              msg, response)) {
     // There was an error establishing communication with the server.
@@ -352,7 +352,7 @@ SyncerError SyncerProtoUtil::PostClientToServerMessage(
     return ServerConnectionErrorAsSyncerError(server_status);
   }
 
-  LogClientToServerResponse(*response);
+  LogClientToServerResponse(*response, session);
 
   browser_sync::SyncProtocolError sync_protocol_error;