Log the sync communication that happens between client and server.

sync/engine/traffic_logger.cc

Index: sync/engine/traffic_logger.cc
diff --git a/sync/engine/traffic_logger.cc b/sync/engine/traffic_logger.cc
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+++ b/sync/engine/traffic_logger.cc
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+// 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/traffic_logger.h"
+
+#include <string>
+
+#include "base/json/json_writer.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
+#include "sync/protocol/proto_value_conversions.h"
+#include "sync/protocol/sync.pb.h"
+
+namespace browser_sync {
+
+namespace {
+template <class T>
+void LogData(const T& data,
+             DictionaryValue* (*to_dictionary_value)(const T&, bool),
+             const std::string& description) {
+  if (::logging::DEBUG_MODE && VLOG_IS_ON(1)) {
+    scoped_ptr<DictionaryValue> value(
+        (*to_dictionary_value)(data, true /* include_specifics */));
+    std::string message;
+    base::JSONWriter::WriteWithOptions(value.get(),
+        base::JSONWriter::OPTIONS_PRETTY_PRINT,
+        &message);
+    DVLOG(1) << "\n" << description << "\n" << message << "\n";
+  }
+}
+}  // namespace
+
+void LogClientToServerMessage(const sync_pb::ClientToServerMessage& msg) {
+  LogData(msg, &ClientToServerMessageToValue,
+          "******Client To Server Message******");
+  // TODO(lipalani) : Store the data (minus specifics)
+  // in a circular buffer in memory.
+}
+
+void LogClientToServerResponse(
+    const sync_pb::ClientToServerResponse& response) {
+  LogData(response, &ClientToServerResponseToValue,
+          "******Server Response******");
+  // TODO(lipalani) : Store the data (minus specifics)
+  // in a circular buffer in memory.
+}
+
+}  // namespace browser_sync