Remove unused lexer code.

mojom/lexer.h

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef MOJO_PUBLIC_TOOLS_BINDINGS_MOJOM_CPP_LEXER_H_
-#define MOJO_PUBLIC_TOOLS_BINDINGS_MOJOM_CPP_LEXER_H_
-
-#include <cstddef>
-#include <string>
-#include <vector>
-
-#include "base/macros.h"
-
-namespace mojo {
-namespace mojom {
-
-enum class TokenType {
-  // Errors
-  ERROR_UNKNOWN,
-  ERROR_ILLEGAL_CHAR,
-  ERROR_UNTERMINATED_STRING_LITERAL,
-
-  // Punctuators and Separators
-  LPAREN,
-  RPAREN,
-  LBRACKET,
-  RBRACKET,
-  LBRACE,
-  RBRACE,
-  LANGLE,
-  RANGLE,
-  SEMI,
-  COMMA,
-  DOT,
-  MINUS,
-  PLUS,
-  AMP,
-  QSTN,
-  EQUALS,
-  RESPONSE,
-
-  // Identifiers
-  IDENTIFIER,
-
-  // Keywords
-  IMPORT,
-  MODULE,
-  STRUCT,
-  UNION,
-  INTERFACE,
-  ENUM,
-  CONST,
-  TRUE,
-  FALSE,
-  DEFAULT,
-
-  // Constants
-  INT_CONST_DEC,
-  INT_CONST_HEX,
-  FLOAT_CONST,
-  ORDINAL,
-  STRING_LITERAL,
-
-  // TODO(azani): Check that all tokens were implemented.
-  // TODO(azani): Error out on octal.
-};
-
-struct Token {
-  Token();
-  ~Token();
-
-  bool error() const {
-    return (token_type == TokenType::ERROR_ILLEGAL_CHAR ||
-            token_type == TokenType::ERROR_UNTERMINATED_STRING_LITERAL ||
-            token_type == TokenType::ERROR_UNKNOWN);
-  }
-
-  TokenType token_type;
-  std::string token;
-  size_t char_pos;
-  size_t line_no;
-  size_t line_pos;
-};
-
-// Accepts the text of a mojom file and returns the ordered list of tokens
-// found in the file.
-std::vector<Token> Tokenize(const std::string& source);
-
-}  // namespace mojom
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_TOOLS_BINDINGS_MOJOM_CPP_LEXER_H_