Add a flag to lexer-shell to replicate input file.

src/lexer/experimental-scanner.h

 // Copyright 2013 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 44 matching lines @@
     int end_pos;
   };
 
   struct SavedToken {
     int beg, end;
     Token::Value value;
   };
 
   ExperimentalScanner(const char* fname,
                       bool read_all_at_once,
-                      Isolate* isolate);
+                      Isolate* isolate,
+                      int repeat);
   ~ExperimentalScanner();
 
   Token::Value Next();
   Token::Value current_token();
   Location location();
 
   void Record(v8::internal::Token::Value token, int beg_pos, int end_pos);
 
  private:
   void FillTokens();
   static const int BUFFER_SIZE = 256;
   std::vector<SavedToken> token_;
   size_t current_;
   size_t fetched_;
   FILE* file_;
   // python generated version
   EvenMoreExperimentalScanner* scanner_;
   // re2c version
   // PushScanner* scanner_;
   bool read_all_at_once_;
   bool already_pushed_;
   const v8::internal::byte* source_;
   int length_;
 };
 
+const byte* ReadFile(const char* name, Isolate* isolate, int* size, int repeat);
+
 } }  // namespace v8::internal
 
 #endif