[Sync] Display the client server traffic log in about:sync.

sync/engine/traffic_recorder.h

 // 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.
 
 #ifndef CHROME_BROWSER_SYNC_ENGINE_TRAFFIC_RECORDER_H_
 #define CHROME_BROWSER_SYNC_ENGINE_TRAFFIC_RECORDER_H_
 #pragma once
 
 #include <deque>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
+#include "base/values.h"
 #include "sync/protocol/sync.pb.h"
 
 namespace sync_pb {
 class ClientToServerResponse;
 class ClientToServerMessage;
 }
 
 namespace browser_sync {
 
 class TrafficRecorder {
@@ skipping 11 matching lines @@
     // If the message is too big to be kept in memory then it should be
     // truncated. For now the entire message is omitted if it is too big.
     // TODO(lipalani): Truncate the specifics to fit within size.
     bool truncated;
 
     TrafficRecord(const std::string& message,
                   TrafficMessageType message_type,
                   bool truncated);
     TrafficRecord();
     ~TrafficRecord();
+
+    DictionaryValue* ToValue() const;
   };
 
   TrafficRecorder(unsigned int max_messages, unsigned int max_message_size);
   ~TrafficRecorder();
 
   void RecordClientToServerMessage(const sync_pb::ClientToServerMessage& msg);
   void RecordClientToServerResponse(
       const sync_pb::ClientToServerResponse& response);
+  ListValue* ToValue() const;
 
   const std::deque<TrafficRecord>& records() {
     return records_;
   }
 
  private:
   void AddTrafficToQueue(TrafficRecord* record);
   void StoreProtoInQueue(const ::google::protobuf::MessageLite& msg,
                          TrafficMessageType type);
 
   // Maximum number of messages stored in the queue.
   unsigned int max_messages_;
 
   // Maximum size of each message.
   unsigned int max_message_size_;
   std::deque<TrafficRecord> records_;
   DISALLOW_COPY_AND_ASSIGN(TrafficRecorder);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_TRAFFIC_RECORDER_H_