Log the sync communication that happens between client and server.

sync/engine/syncer_proto_util.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/engine/syncer_proto_util.h"
 
 #include "base/format_macros.h"
+#include "base/json/json_writer.h"
 #include "base/stringprintf.h"
 #include "sync/engine/net/server_connection_manager.h"
 #include "sync/engine/syncer.h"
 #include "sync/engine/syncer_types.h"
+#include "sync/engine/traffic_logger.h"
 #include "sync/protocol/service_constants.h"
 #include "sync/protocol/sync.pb.h"
 #include "sync/protocol/sync_enums.pb.h"
 #include "sync/protocol/sync_protocol_error.h"
 #include "sync/sessions/sync_session.h"
 #include "sync/syncable/model_type.h"
 #include "sync/syncable/syncable-inl.h"
 #include "sync/syncable/syncable.h"
 #include "sync/util/time.h"
 
@@ skipping 308 matching lines @@
     SyncSession* session) {
 
   CHECK(response);
   DCHECK(!msg.get_updates().has_from_timestamp());  // Deprecated.
   DCHECK(!msg.get_updates().has_requested_types());  // Deprecated.
   DCHECK(msg.has_store_birthday() || IsVeryFirstGetUpdates(msg))
       << "Must call AddRequestBirthday to set birthday.";
 
   syncable::Directory* dir = session->context()->directory();
 
+  LogClientToServerMessage(msg);
   if (!PostAndProcessHeaders(session->context()->connection_manager(), session,
                              msg, response)) {
     // There was an error establishing communication with the server.
     // We can not proceed beyond this point.
     const browser_sync::HttpResponse::ServerConnectionCode server_status =
         session->context()->connection_manager()->server_status();
 
     DCHECK_NE(server_status, browser_sync::HttpResponse::NONE);
     DCHECK_NE(server_status, browser_sync::HttpResponse::SERVER_CONNECTION_OK);
 
     return ServerConnectionErrorAsSyncerError(server_status);
   }
 
+  LogClientToServerResponse(*response);
+
   browser_sync::SyncProtocolError sync_protocol_error;
 
   // Birthday mismatch overrides any error that is sent by the server.
   if (!VerifyResponseBirthday(dir, response)) {
     sync_protocol_error.error_type = browser_sync::NOT_MY_BIRTHDAY;
      sync_protocol_error.action =
          browser_sync::DISABLE_SYNC_ON_CLIENT;
   } else if (response->has_error()) {
     // This is a new server. Just get the error from the protocol.
     sync_protocol_error = ConvertErrorPBToLocalType(response->error());
@@ skipping 165 matching lines @@
 std::string SyncerProtoUtil::ClientToServerResponseDebugString(
     const sync_pb::ClientToServerResponse& response) {
   // Add more handlers as needed.
   std::string output;
   if (response.has_get_updates())
     output.append(GetUpdatesResponseString(response.get_updates()));
   return output;
 }
 
 }  // namespace browser_sync