Tracing: Added necessary plumbing to make sure clocksync metadata events are always included.

base/trace_event/trace_event_unittest.cc

Index: base/trace_event/trace_event_unittest.cc
diff --git a/base/trace_event/trace_event_unittest.cc b/base/trace_event/trace_event_unittest.cc
index 25a6d5f3f6213508b9fcc838179038a597252ec1..b47524d3e86c44f01e859b381aa7f22d282b5cfb 100644
--- a/base/trace_event/trace_event_unittest.cc
+++ b/base/trace_event/trace_event_unittest.cc
@@ -1257,13 +1257,11 @@ TEST_F(TraceEventTestFixture, AddMetadataEvent) {
   std::unique_ptr<ConvertableToTraceFormat> conv1(new Convertable(&num_calls));
   std::unique_ptr<Convertable> conv2(new Convertable(&num_calls));
 
-  BeginTrace();
-  TRACE_EVENT_API_ADD_METADATA_EVENT(
-      TraceLog::GetCategoryGroupEnabled("__metadata"), "metadata_event_1",
-      "metadata_arg_name", std::move(conv1));
-  TRACE_EVENT_API_ADD_METADATA_EVENT(
-      TraceLog::GetCategoryGroupEnabled("__metadata"), "metadata_event_2",
-      "metadata_arg_name", std::move(conv2));
+  BeginSpecificTrace("irrelevant_cat");
+  TRACE_EVENT_METADATA_FORCED1("metadata_event_1", "metadata_arg_name",
+                               std::move(conv1));
+  TRACE_EVENT_METADATA_FORCED1("metadata_event_2", "metadata_arg_name",
+                               std::move(conv2));
   // |AppendAsTraceFormat| should only be called on flush, not when the event
   // is added.
   ASSERT_EQ(0, num_calls);