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

content/browser/tracing/power_tracing_agent.cc

Index: content/browser/tracing/power_tracing_agent.cc
diff --git a/content/browser/tracing/power_tracing_agent.cc b/content/browser/tracing/power_tracing_agent.cc
index 6139db8703a1323de94290c32fb386ffd3a85ef2..175913ec4e749c6e18f223ae24fb8fef01cddd90 100644
--- a/content/browser/tracing/power_tracing_agent.cc
+++ b/content/browser/tracing/power_tracing_agent.cc
@@ -115,7 +115,7 @@ bool PowerTracingAgent::SupportsExplicitClockSync() {
 }
 
 void PowerTracingAgent::RecordClockSyncMarker(
-    int sync_id,
+    const std::string& sync_id,
     const RecordClockSyncMarkerCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(SupportsExplicitClockSync());
@@ -129,7 +129,7 @@ void PowerTracingAgent::RecordClockSyncMarker(
 }
 
 void PowerTracingAgent::RecordClockSyncMarkerOnThread(
-    int sync_id,
+    const std::string& sync_id,
     const RecordClockSyncMarkerCallback& callback) {
   DCHECK(thread_.task_runner()->BelongsToCurrentThread());
   DCHECK(SupportsExplicitClockSync());