[SyncFS] Add EVENT_TRACE to SyncTaskToken

chrome/browser/sync_file_system/task_logger.h

 // Copyright 2014 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_FILE_SYSTEM_TASK_LOGGER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_TASK_LOGGER_H_
 
 #include <deque>
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/time/time.h"
 
 namespace sync_file_system {
 
 class TaskLogger : public base::SupportsWeakPtr<TaskLogger> {
  public:
   struct TaskLog {
+    int log_id;
     base::TimeTicks start_time;
     base::TimeTicks end_time;
     std::string task_description;
     std::string result_description;
     std::vector<std::string> details;
 
     TaskLog();
     ~TaskLog();
   };
 
@@ skipping 26 matching lines @@
   std::deque<TaskLog*> log_history_;
 
   ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskLogger);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_TASK_LOGGER_H_