Changed interface to preparser to not require pushback support.

include/v8-preparser.h

 // Copyright 2010 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 81 matching lines @@
 
 
 // Interface for a stream of Unicode characters.
 class UnicodeInputStream {
  public:
   virtual ~UnicodeInputStream();
 
   // Returns the next Unicode code-point in the input, or a negative value when
   // there is no more input in the stream.
   virtual int32_t Next() = 0;
-
-  // Pushes a read character back into the stream, so that it will be the next
-  // to be read by Advance(). The character pushed back must be the most
-  // recently read character that hasn't already been pushed back (i.e., if
-  // pushing back more than one character, they must occur in the opposite order
-  // of the one they were read in).
-  virtual void PushBack(int32_t ch) = 0;
 };
 
 
 // Preparse a JavaScript program. The source code is provided as a
 // UnicodeInputStream. The max_stack_size limits the amount of stack
 // space that the preparser is allowed to use. If the preparser uses
 // more stack space than the limit provided, the result's stack_overflow()
 // method will return true. Otherwise the result contains preparser
 // data that can be used by the V8 parser to speed up parsing.
 PreParserData V8EXPORT Preparse(UnicodeInputStream* input,
                                 size_t max_stack_size);
 
 }  // namespace v8.
 
 #endif  // PREPARSER_H