tracing: Fix reading member without lock

Change-Id: Id7450cd05f2e9263e4573a89290519a5649c4f4b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2361538
Auto-Submit: ssid <ssid@chromium.org>
Reviewed-by: Eric Seckler <eseckler@chromium.org>
Commit-Queue: ssid <ssid@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799341}

services/tracing/public/cpp/perfetto/trace_event_data_source.cc

@@ -301,7 +301,7 @@ void TraceEventMetadataSource::GenerateMetadata(
   trace_packet->set_timestamp_clock_id(kTraceClockId);
   auto* chrome_metadata = trace_packet->set_chrome_metadata();
   for (auto& generator : *proto_generators) {
-    generator.Run(chrome_metadata, privacy_filtering_enabled_);
+    generator.Run(chrome_metadata, privacy_filtering_enabled);
   }
 
   if (privacy_filtering_enabled) {