[Tracing] Update sync_id to be string type for clock sync

content/browser/tracing/power_tracing_agent.cc

 // Copyright 2015 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 "base/lazy_instance.h"
 #include "base/memory/singleton.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event_impl.h"
 #include "content/browser/tracing/battor_power_trace_provider.h"
 #include "content/browser/tracing/power_tracing_agent.h"
@@ skipping 97 matching lines @@
                  base::Unretained(this),
                  callback,
                  result));
 }
 
 bool PowerTracingAgent::SupportsExplicitClockSync() {
   return true;
 }
 
 void PowerTracingAgent::RecordClockSyncMarker(
-    int sync_id,
+    const std::string& sync_id,
     const RecordClockSyncMarkerCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(SupportsExplicitClockSync());
 
   thread_.task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&PowerTracingAgent::RecordClockSyncMarkerOnThread,
                  base::Unretained(this),
                  sync_id,
                  callback));
 }
 
 void PowerTracingAgent::RecordClockSyncMarkerOnThread(
-    int sync_id,
+    const std::string& sync_id,
     const RecordClockSyncMarkerCallback& callback) {
   DCHECK(thread_.task_runner()->BelongsToCurrentThread());
   DCHECK(SupportsExplicitClockSync());
 
   base::TimeTicks issue_ts = base::TimeTicks::Now();
   battor_trace_provider_->RecordClockSyncMarker(sync_id);
   base::TimeTicks issue_end_ts = base::TimeTicks::Now();
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(callback, sync_id, issue_ts, issue_end_ts));
 }
 
 }  // namespace content