Use correct thread ids in Track::ThreadScoped()

Perfetto embedders (e.g. Chromium) can provide their own platforms
for stuff like determining thread ids. ThreadTrack::Current()
correctly calls into tracing muxer methods to get thread id from
the platform. Track::ThreadScoped() should do the same to avoid
inconsistencies.

Bug: 339835280
Change-Id: I43c8b2cdd5666a690451b68b1b4f01234242d488

2 files changed, 8 insertions, 5 deletions

diff --git a/include/perfetto/tracing/track.h b/include/perfetto/tracing/track.h
index f17ffbbeb..37f02e585 100644
--- a/include/perfetto/tracing/track.h
+++ b/include/perfetto/tracing/track.h
@@ -120,11 +120,7 @@ struct PERFETTO_EXPORT_COMPONENT Track {
   // Construct a track using |ptr| as identifier within thread-scope.
   // Shorthand for `Track::FromPointer(ptr, ThreadTrack::Current())`
   // Usage: TRACE_EVENT_BEGIN("...", "...", perfetto::Track::ThreadScoped(this))
-  static Track ThreadScoped(
-      const void* ptr,
-      Track parent = MakeThreadTrack(base::GetThreadId())) {
-    return Track::FromPointer(ptr, parent);
-  }
+  static Track ThreadScoped(const void* ptr, Track parent = Track());
 
  protected:
   constexpr Track(uint64_t uuid_, uint64_t parent_uuid_)
diff --git a/src/tracing/track.cc b/src/tracing/track.cc
index b7d979516..02e6e035e 100644
--- a/src/tracing/track.cc
+++ b/src/tracing/track.cc
@@ -49,6 +49,13 @@ void Track::Serialize(protos::pbzero::TrackDescriptor* desc) const {
   desc->AppendRawProtoBytes(bytes.data(), bytes.size());
 }
 
+// static
+Track Track::ThreadScoped(const void* ptr, Track parent) {
+  if (parent.uuid == 0)
+    return Track::FromPointer(ptr, ThreadTrack::Current());
+  return Track::FromPointer(ptr, parent);
+}
+
 protos::gen::TrackDescriptor ProcessTrack::Serialize() const {
   auto desc = Track::Serialize();
   auto pd = desc.mutable_process();