Experimental parser: crash fix.

src/preparser.h

 // Copyright 2012 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 31 matching lines @@
   ParserBase(ScannerBase* scanner, uintptr_t stack_limit)
       : scanner_(scanner),
         stack_limit_(stack_limit),
         stack_overflow_(false),
         allow_lazy_(false),
         allow_natives_syntax_(false),
         allow_generators_(false),
         allow_for_of_(false) { }
   // TODO(mstarzinger): Only virtual until message reporting has been unified.
   // FIXME: Might need to continue to be virtual for the experimental branch.
-  virtual ~ParserBase() {
-    delete scanner_;
-    scanner_ = NULL;
-  }
+  virtual ~ParserBase() { }
 
   // Getters that indicate whether certain syntactical constructs are
   // allowed to be parsed by this instance of the parser.
   bool allow_lazy() const { return allow_lazy_; }
   bool allow_natives_syntax() const { return allow_natives_syntax_; }
   bool allow_generators() const { return allow_generators_; }
   bool allow_for_of() const { return allow_for_of_; }
   bool allow_modules() const { return scanner()->HarmonyModules(); }
   bool allow_harmony_scoping() const { return scanner()->HarmonyScoping(); }
   bool allow_harmony_numeric_literals() const {
@@ skipping 623 matching lines @@
   ParserRecorder* log_;
   Scope* scope_;
   ScannerBase::Location strict_mode_violation_location_;
   const char* strict_mode_violation_type_;
   bool parenthesized_function_;
 };
 
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H