Sane asynchronous debugging and stack traces

runtime/vm/service.cc

Index: runtime/vm/service.cc
diff --git a/runtime/vm/service.cc b/runtime/vm/service.cc
index bdc71e989bc89aeac33119903309465443afa505..e43f64ec8e75f5942bf1248cefe4a9a1f624b06e 100644
--- a/runtime/vm/service.cc
+++ b/runtime/vm/service.cc
@@ -1334,6 +1334,9 @@ static bool GetStack(Thread* thread, JSONStream* js) {
   }
   ASSERT(isolate->compilation_allowed());
   DebuggerStackTrace* stack = isolate->debugger()->StackTrace();
+  DebuggerStackTrace* async_return_stack =
+      isolate->debugger()->AsyncReturnStack();
+
   // Do we want the complete script object and complete local variable objects?
   // This is true for dump requests.
   const bool full = BoolParameter::Parse(js->LookupParam("_full"), false);
@@ -1351,6 +1354,18 @@ static bool GetStack(Thread* thread, JSONStream* js) {
     }
   }
 
+  if (async_return_stack != NULL) {
+    JSONArray jsarr(&jsobj, "asyncFrames");
+
+    intptr_t num_frames = async_return_stack->Length();
+    for (intptr_t i = 0; i < num_frames; i++) {
+      ActivationFrame* frame = async_return_stack->FrameAt(i);
+      JSONObject jsobj(&jsarr);
+      frame->PrintToJSONObject(&jsobj, full);
+      jsobj.AddProperty("index", i);
+    }
+  }
+
   {
     MessageHandler::AcquiredQueues aq(isolate->message_handler());
     jsobj.AddProperty("messages", aq.queue());