[vm] Support flow events in Dart_TimelineEvent.

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
diff --git a/runtime/vm/dart_api_impl.cc b/runtime/vm/dart_api_impl.cc
index 69b52f18c8d6c8aeff2cc648c500281f9e5596fa..e3ff1184fdabd80d6f99570fa66f0f860eddfaf6 100644
--- a/runtime/vm/dart_api_impl.cc
+++ b/runtime/vm/dart_api_impl.cc
@@ -6474,7 +6474,7 @@ DART_EXPORT void Dart_TimelineEvent(const char* label,
   if (type < Dart_Timeline_Event_Begin) {
     return;
   }
-  if (type > Dart_Timeline_Event_Counter) {
+  if (type > Dart_Timeline_Event_Flow_End) {
     return;
   }
   TimelineStream* stream = Timeline::GetEmbedderStream();
@@ -6509,6 +6509,15 @@ DART_EXPORT void Dart_TimelineEvent(const char* label,
     case Dart_Timeline_Event_Counter:
       event->Counter(label, timestamp0);
       break;
+    case Dart_Timeline_Event_Flow_Begin:
+      event->FlowBegin(label, timestamp1_or_async_id, timestamp0);
+      break;
+    case Dart_Timeline_Event_Flow_Step:
+      event->FlowStep(label, timestamp1_or_async_id, timestamp0);
+      break;
+    case Dart_Timeline_Event_Flow_End:
+      event->FlowEnd(label, timestamp1_or_async_id, timestamp0);
+      break;
     default:
       FATAL("Unknown Dart_Timeline_Event_Type");
   }