Implement rewind: drop one or more frames from the debugger.

runtime/vm/json_stream.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_JSON_STREAM_H_
 #define RUNTIME_VM_JSON_STREAM_H_
 
 #include "include/dart_api.h"  // for Dart_Port
 #include "platform/text_buffer.h"
 #include "vm/allocation.h"
@@ skipping 35 matching lines @@
   kInternalError = -32603,
 
   kExtensionError = -32000,
 
   kFeatureDisabled = 100,
   kCannotAddBreakpoint = 102,
   kStreamAlreadySubscribed = 103,
   kStreamNotSubscribed = 104,
   kIsolateMustBeRunnable = 105,
   kIsolateMustBePaused = 106,
+  kCannotResume = 107,
 
   // Experimental (used in private rpcs).
   kIsolateIsReloading = 1000,
   kFileSystemAlreadyExists = 1001,
   kFileSystemDoesNotExist = 1002,
   kFileDoesNotExist = 1003,
   kIsolateReloadFailed = 1004,
   kIsolateReloadBarred = 1005,
 };
 
@@ skipping 338 matching lines @@
 
   friend class JSONObject;
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(JSONArray);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_JSON_STREAM_H_