Implement breakpoint for closure calls

runtime/vm/code_patcher.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.
 // Class for patching compiled code.
 
 #ifndef VM_CODE_PATCHER_H_
 #define VM_CODE_PATCHER_H_
 
 #include "vm/allocation.h"
 
@@ skipping 38 matching lines @@
   static uword GetStaticCallTargetAt(uword return_address, const Code& code);
 
   // Get instance call information.  Returns the call target and sets each
   // of the output parameters ic_data and arguments_descriptor if they are
   // non-NULL.
   static uword GetInstanceCallAt(uword return_address,
                                  const Code& code,
                                  ICData* ic_data,
                                  Array* arguments_descriptor);
 
+  // Return the arguments descriptor array of the closure call
+  // before the given return address.
+  static RawArray* GetClosureArgDescAt(uword return_address,
+                                       const Code& code);
+
   static intptr_t InstanceCallSizeInBytes();
 
   static void InsertCallAt(uword start, uword target);
 };
 
 }  // namespace dart
 
 #endif  // VM_CODE_PATCHER_H_