Fixes a problem with the recovery of contexts in the debugger at closure calls.

runtime/vm/debugger.h

 // Copyright (c) 2012, 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 VM_DEBUGGER_H_
 #define VM_DEBUGGER_H_
 
 #include "include/dart_debugger_api.h"
 
 #include "vm/object.h"
@@ skipping 159 matching lines @@
                   intptr_t* end_pos,
                   Instance* value);
 
   RawArray* GetLocalVariables();
   RawContext* GetSavedEntryContext();
   RawContext* GetSavedCurrentContext();
 
   void PrintToJSONObject(JSONObject* jsobj);
 
  private:
+  void PrintContextMismatchError(const String& var_name,
+                                 intptr_t ctx_slot,
+                                 intptr_t frame_ctx_level,
+                                 intptr_t var_ctx_level);
+
   intptr_t PcDescIndex();
   intptr_t TryIndex();
   void GetPcDescriptors();
   void GetVarDescriptors();
   void GetDescIndices();
 
   RawObject* GetLocalVar(intptr_t slot_index);
   RawInstance* GetLocalInstanceVar(intptr_t slot_index);
   RawContext* GetLocalContextVar(intptr_t slot_index);
 
@@ skipping 297 matching lines @@
 
   friend class Isolate;
   friend class SourceBreakpoint;
   DISALLOW_COPY_AND_ASSIGN(Debugger);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_DEBUGGER_H_