tracing: Fix track_uuid association for typed events.

crrev.com/c/2633994 introduced a bug which caused some events to be
emitted on an incorrect track. It's caused by the incorrect assumption
that a constexpr symbol (kDefaultTrack) only receives a single address
within a translation unit, even across different inlined functions.

This patch fixes this by making kDefaultTrack a const symbol instead.

Change-Id: I3f8a1d569d50839bb2188a037f88b9d6d3d7253b
Bug: 1168791
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2644798
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Auto-Submit: Eric Seckler <eseckler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#846112}

base/trace_event/typed_macros_internal.h

@@ -59,7 +59,7 @@
 
 namespace trace_event_internal {
 
-static constexpr perfetto::Track kDefaultTrack{};
+static const perfetto::Track kDefaultTrack{};
 
 // Copy of function with the same name from Perfetto client library.
 template <typename T>

base/trace_event/typed_macros_unittest.cc

@@ -232,39 +232,73 @@ TEST_F(TypedTraceEventTest, InternedData) {
 TEST_F(TypedTraceEventTest, InstantThreadEvent) {
   TraceLog::GetInstance()->SetEnabled(TraceConfig(kRecordAllCategoryFilter, ""),
                                       TraceLog::RECORDING_MODE);
+
   TRACE_EVENT_INSTANT("cat", "ThreadEvent", [](perfetto::EventContext) {});
   auto track_event = ParseTrackEvent();
   EXPECT_FALSE(track_event.has_track_uuid());
+
+  CancelTrace();
 }
 
 TEST_F(TypedTraceEventTest, InstantProcessEvent) {
   TraceLog::GetInstance()->SetEnabled(TraceConfig(kRecordAllCategoryFilter, ""),
                                       TraceLog::RECORDING_MODE);
+
   TRACE_EVENT_INSTANT("cat", "ProcessEvent", perfetto::ProcessTrack::Current(),
                       [](perfetto::EventContext) {});
   auto track_event = ParseTrackEvent();
   EXPECT_TRUE(track_event.has_track_uuid());
   EXPECT_EQ(track_event.track_uuid(), perfetto::ProcessTrack::Current().uuid);
+
+  CancelTrace();
 }
 
 TEST_F(TypedTraceEventTest, InstantGlobalEvent) {
   TraceLog::GetInstance()->SetEnabled(TraceConfig(kRecordAllCategoryFilter, ""),
                                       TraceLog::RECORDING_MODE);
+
   TRACE_EVENT_INSTANT("cat", "GlobalEvent", perfetto::Track::Global(1234),
                       [](perfetto::EventContext) {});
   auto track_event = ParseTrackEvent();
   EXPECT_TRUE(track_event.has_track_uuid());
   EXPECT_EQ(track_event.track_uuid(), perfetto::Track::Global(1234).uuid);
+
+  CancelTrace();
 }
 
 TEST_F(TypedTraceEventTest, InstantGlobalDefaultEvent) {
   TraceLog::GetInstance()->SetEnabled(TraceConfig(kRecordAllCategoryFilter, ""),
                                       TraceLog::RECORDING_MODE);
+
   TRACE_EVENT_INSTANT("cat", "GlobalDefaultEvent", perfetto::Track::Global(0),
                       [](perfetto::EventContext) {});
   auto track_event = ParseTrackEvent();
   EXPECT_TRUE(track_event.has_track_uuid());
   EXPECT_EQ(track_event.track_uuid(), perfetto::Track::Global(0).uuid);
+
+  CancelTrace();
+}
+
+TEST_F(TypedTraceEventTest, BeginEventOnDefaultTrackDoesNotWriteTrackUuid) {
+  TraceLog::GetInstance()->SetEnabled(TraceConfig(kRecordAllCategoryFilter, ""),
+                                      TraceLog::RECORDING_MODE);
+
+  TRACE_EVENT_BEGIN("cat", "Name");
+  auto begin_event = ParseTrackEvent();
+  EXPECT_FALSE(begin_event.has_track_uuid());
+
+  CancelTrace();
+}
+
+TEST_F(TypedTraceEventTest, EndEventOnDefaultTrackDoesNotWriteTrackUuid) {
+  TraceLog::GetInstance()->SetEnabled(TraceConfig(kRecordAllCategoryFilter, ""),
+                                      TraceLog::RECORDING_MODE);
+
+  TRACE_EVENT_END("cat");
+  auto end_event = ParseTrackEvent();
+  EXPECT_FALSE(end_event.has_track_uuid());
+
+  CancelTrace();
 }
 
 }  // namespace trace_event