Add step OverAwait to service protocol

runtime/vm/service_event.cc

Index: runtime/vm/service_event.cc
diff --git a/runtime/vm/service_event.cc b/runtime/vm/service_event.cc
index 314d6359bb34a145891360397d15b6285c6e52e0..2e64c66a7dd2185daaad046daa77de20a2da4883 100644
--- a/runtime/vm/service_event.cc
+++ b/runtime/vm/service_event.cc
@@ -44,7 +44,6 @@ ServiceEvent::ServiceEvent(Isolate* isolate, EventKind event_kind)
       top_frame_(NULL),
       extension_rpc_(NULL),
       exception_(NULL),
-      async_continuation_(NULL),
       at_async_jump_(false),
       inspectee_(NULL),
       gc_stats_(NULL),
@@ -67,7 +66,7 @@ ServiceEvent::ServiceEvent(const DebuggerEvent* debugger_event)
       top_frame_(NULL),
       extension_rpc_(NULL),
       exception_(NULL),
-      async_continuation_(NULL),
+      at_async_jump_(false),
       inspectee_(NULL),
       gc_stats_(NULL),
       bytes_(NULL),
@@ -76,7 +75,6 @@ ServiceEvent::ServiceEvent(const DebuggerEvent* debugger_event)
   DebuggerEvent::EventType type = debugger_event->type();
   if (type == DebuggerEvent::kBreakpointReached) {
     set_breakpoint(debugger_event->breakpoint());
-    set_async_continuation(debugger_event->async_continuation());
     set_at_async_jump(debugger_event->at_async_jump());
   }
   if (type == DebuggerEvent::kExceptionThrown) {
@@ -222,9 +220,8 @@ void ServiceEvent::PrintJSON(JSONStream* js) const {
   if (exception() != NULL) {
     jsobj.AddProperty("exception", *(exception()));
   }
-  if (async_continuation() != NULL && !async_continuation()->IsNull()) {
-    jsobj.AddProperty("_asyncContinuation", *(async_continuation()));
-    jsobj.AddProperty("_atAsyncJump", at_async_jump());
+  if (at_async_jump()) {
+    jsobj.AddProperty("atAsyncSuspension", true);
   }
   if (inspectee() != NULL) {
     jsobj.AddProperty("inspectee", *(inspectee()));