Optimize Parallel Trace Serialization for LevelDB Writes

PiperOrigin-RevId: 899423023

Author: Profiler Team

xprof/convert/trace_viewer/BUILD

@@ -157,6 +157,7 @@ cc_library(
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/synchronization",
         "@com_google_absl//absl/time",
         "@com_google_protobuf//:protobuf",
         "@org_xprof//plugin/xprof/protobuf:task_proto_cc",