tree 41aa34d4e3bbf5cbee2e591636906839e47bd3e0
parent c5bfccc6fb1def32c9672569cffbb0a038a6c31b
author Ben Konyi <bkonyi@google.com> 1547659682 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1547659682 +0000

[ VM / Debugger ] Fix issue where a 'Step' command issued when there's no stack caused a crash.

For example, running this sample, pausing the isolate, and stepping
would crash, whereas we would expect to pause in the ServerSocket.listen
callback.

```
import 'dart:io';

main() {
  ServerSocket.bind('127.0.0.1', 22000).then((s) {
    s.listen((m) { // Should pause here on socket connection after step.
      print(m);
    });
  });
}
```

Fixes #35601.

Change-Id: I2155de1cface159f92734d3112b6e17c35ab7550
Reviewed-on: https://dart-review.googlesource.com/c/89780
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>