Fix usage of NULL in integer contexts.

src/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 702 matching lines @@
 Statement PreParser<Scanner, Log>::ParseThrowStatement(bool* ok) {
   // ThrowStatement ::
   //   'throw' [no line terminator] Expression ';'
 
   Expect(i::Token::THROW, CHECK_OK);
   if (scanner_->has_line_terminator_before_next()) {
     typename Scanner::Location pos = scanner_->location();
     ReportMessageAt(pos.beg_pos, pos.end_pos,
                     "newline_after_throw", NULL);
     *ok = false;
-    return NULL;
+    return kUnknownStatement;
   }
   ParseExpression(true, CHECK_OK);
   ExpectSemicolon(CHECK_OK);
 
   return kUnknownStatement;
 }
 
 
 template <typename Scanner, typename Log>
 Statement PreParser<Scanner, Log>::ParseTryStatement(bool* ok) {
@@ skipping 265 matching lines @@
 
 
 template <typename Scanner, typename Log>
 Expression PreParser<Scanner, Log>::ParseMemberWithNewPrefixesExpression(
     unsigned new_count, bool* ok) {
   // MemberExpression ::
   //   (PrimaryExpression | FunctionLiteral)
   //     ('[' Expression ']' | '.' Identifier | Arguments)*
 
   // Parse the initial primary or function expression.
-  Expression result = NULL;
+  Expression result = kUnknownExpression;
   if (peek() == i::Token::FUNCTION) {
     Consume(i::Token::FUNCTION);
     if (peek() == i::Token::IDENTIFIER) {
       ParseIdentifier(CHECK_OK);
     }
     result = ParseFunctionLiteral(CHECK_OK);
   } else {
     result = ParsePrimaryExpression(CHECK_OK);
   }
 
@@ skipping 390 matching lines @@
     *is_get = strncmp(token, "get", 3) == 0;
     *is_set = !*is_get && strncmp(token, "set", 3) == 0;
   }
   return GetIdentifierSymbol();
 }
 
 #undef CHECK_OK
 } }  // v8::preparser
 
 #endif  // V8_PREPARSER_H