Step next should respect do/while condition block.

src/ast.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 304 matching lines @@
 
  private:
   Statement* body_;
   BreakTarget continue_target_;
 };
 
 
 class DoWhileStatement: public IterationStatement {
  public:
   explicit DoWhileStatement(ZoneStringList* labels)
-      : IterationStatement(labels), cond_(NULL) {
+      : IterationStatement(labels), cond_(NULL), condition_position_(-1) {
   }
 
   void Initialize(Expression* cond, Statement* body) {
     IterationStatement::Initialize(body);
     cond_ = cond;
   }
 
   virtual void Accept(AstVisitor* v);
 
   Expression* cond() const { return cond_; }
 
+  // Position where condition expression starts. We need it to make
+  // the loop's condition a breakable location.
+  int condition_position() { return condition_position_; }
+  void set_condition_position(int pos) { condition_position_ = pos; }
+
  private:
   Expression* cond_;
+  int condition_position_;
 };
 
 
 class WhileStatement: public IterationStatement {
  public:
   explicit WhileStatement(ZoneStringList* labels)
       : IterationStatement(labels),
         cond_(NULL),
         may_have_function_literal_(true) {
   }
@@ skipping 1425 matching lines @@
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_