[SyncFS] Add EVENT_TRACE to SyncTaskToken

chrome/browser/sync_file_system/drive_backend/sync_task_token.cc

Index: chrome/browser/sync_file_system/drive_backend/sync_task_token.cc
diff --git a/chrome/browser/sync_file_system/drive_backend/sync_task_token.cc b/chrome/browser/sync_file_system/drive_backend/sync_task_token.cc
index a4b911ef17548136d752e5f117532642f788dae7..ffd8ca86974502341ef5bee290e1775120b0e514 100644
--- a/chrome/browser/sync_file_system/drive_backend/sync_task_token.cc
+++ b/chrome/browser/sync_file_system/drive_backend/sync_task_token.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/sync_file_system/drive_backend/sync_task_token.h"
 
 #include "base/bind.h"
+#include "base/debug/trace_event.h"
 #include "chrome/browser/sync_file_system/drive_backend/sync_task_manager.h"
 #include "chrome/browser/sync_file_system/drive_backend/task_dependency_manager.h"
 
@@ -97,9 +98,19 @@ void SyncTaskToken::InitializeTaskLog(const std::string& task_description) {
   task_log_.reset(new TaskLogger::TaskLog);
   task_log_->start_time = base::TimeTicks::Now();
   task_log_->task_description = task_description;
+
+  TRACE_EVENT_ASYNC_BEGIN1(
+      TRACE_DISABLED_BY_DEFAULT("SyncFileSystem"),
+      "SyncTask", task_log_->log_id,
+      "task_description", task_description);
 }
 
 void SyncTaskToken::FinalizeTaskLog(const std::string& result_description) {
+  TRACE_EVENT_ASYNC_END1(
+      TRACE_DISABLED_BY_DEFAULT("SyncFileSystem"),
+      "SyncTask", task_log_->log_id,
+      "result_description", result_description);
+
   DCHECK(task_log_);
   task_log_->result_description = result_description;
   task_log_->end_time = base::TimeTicks::Now();