diff --git a/src/parsing/scanner.h b/src/parsing/scanner.h
new file mode 100644
index 0000000..1d0aba0
--- /dev/null
+++ b/src/parsing/scanner.h
@@ -0,0 +1,760 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Features shared by parsing and pre-parsing scanners.
+
+#ifndef V8_PARSING_SCANNER_H_
+#define V8_PARSING_SCANNER_H_
+
+#include "src/allocation.h"
+#include "src/base/logging.h"
+#include "src/char-predicates.h"
+#include "src/globals.h"
+#include "src/hashmap.h"
+#include "src/list.h"
+#include "src/parsing/token.h"
+#include "src/unicode.h"
+#include "src/unicode-decoder.h"
+#include "src/utils.h"
+
+namespace v8 {
+namespace internal {
+
+
+class AstRawString;
+class AstValueFactory;
+class ParserRecorder;
+class UnicodeCache;
+
+
+// ---------------------------------------------------------------------
+// Buffered stream of UTF-16 code units, using an internal UTF-16 buffer.
+// A code unit is a 16 bit value representing either a 16 bit code point
+// or one part of a surrogate pair that make a single 21 bit code point.
+
+class Utf16CharacterStream {
+ public:
+  Utf16CharacterStream() : pos_(0) { }
+  virtual ~Utf16CharacterStream() { }
+
+  // Returns and advances past the next UTF-16 code unit in the input
+  // stream. If there are no more code units, it returns a negative
+  // value.
+  inline uc32 Advance() {
+    if (buffer_cursor_ < buffer_end_ || ReadBlock()) {
+      pos_++;
+      return static_cast<uc32>(*(buffer_cursor_++));
+    }
+    // Note: currently the following increment is necessary to avoid a
+    // parser problem! The scanner treats the final kEndOfInput as
+    // a code unit with a position, and does math relative to that
+    // position.
+    pos_++;
+
+    return kEndOfInput;
+  }
+
+  // Return the current position in the code unit stream.
+  // Starts at zero.
+  inline size_t pos() const { return pos_; }
+
+  // Skips forward past the next code_unit_count UTF-16 code units
+  // in the input, or until the end of input if that comes sooner.
+  // Returns the number of code units actually skipped. If less
+  // than code_unit_count,
+  inline size_t SeekForward(size_t code_unit_count) {
+    size_t buffered_chars = buffer_end_ - buffer_cursor_;
+    if (code_unit_count <= buffered_chars) {
+      buffer_cursor_ += code_unit_count;
+      pos_ += code_unit_count;
+      return code_unit_count;
+    }
+    return SlowSeekForward(code_unit_count);
+  }
+
+  // Pushes back the most recently read UTF-16 code unit (or negative
+  // value if at end of input), i.e., the value returned by the most recent
+  // call to Advance.
+  // Must not be used right after calling SeekForward.
+  virtual void PushBack(int32_t code_unit) = 0;
+
+  virtual bool SetBookmark();
+  virtual void ResetToBookmark();
+
+ protected:
+  static const uc32 kEndOfInput = -1;
+
+  // Ensures that the buffer_cursor_ points to the code_unit at
+  // position pos_ of the input, if possible. If the position
+  // is at or after the end of the input, return false. If there
+  // are more code_units available, return true.
+  virtual bool ReadBlock() = 0;
+  virtual size_t SlowSeekForward(size_t code_unit_count) = 0;
+
+  const uint16_t* buffer_cursor_;
+  const uint16_t* buffer_end_;
+  size_t pos_;
+};
+
+
+// ---------------------------------------------------------------------
+// DuplicateFinder discovers duplicate symbols.
+
+class DuplicateFinder {
+ public:
+  explicit DuplicateFinder(UnicodeCache* constants)
+      : unicode_constants_(constants),
+        backing_store_(16),
+        map_(&Match) { }
+
+  int AddOneByteSymbol(Vector<const uint8_t> key, int value);
+  int AddTwoByteSymbol(Vector<const uint16_t> key, int value);
+  // Add a a number literal by converting it (if necessary)
+  // to the string that ToString(ToNumber(literal)) would generate.
+  // and then adding that string with AddOneByteSymbol.
+  // This string is the actual value used as key in an object literal,
+  // and the one that must be different from the other keys.
+  int AddNumber(Vector<const uint8_t> key, int value);
+
+ private:
+  int AddSymbol(Vector<const uint8_t> key, bool is_one_byte, int value);
+  // Backs up the key and its length in the backing store.
+  // The backup is stored with a base 127 encoding of the
+  // length (plus a bit saying whether the string is one byte),
+  // followed by the bytes of the key.
+  uint8_t* BackupKey(Vector<const uint8_t> key, bool is_one_byte);
+
+  // Compare two encoded keys (both pointing into the backing store)
+  // for having the same base-127 encoded lengths and representation.
+  // and then having the same 'length' bytes following.
+  static bool Match(void* first, void* second);
+  // Creates a hash from a sequence of bytes.
+  static uint32_t Hash(Vector<const uint8_t> key, bool is_one_byte);
+  // Checks whether a string containing a JS number is its canonical
+  // form.
+  static bool IsNumberCanonical(Vector<const uint8_t> key);
+
+  // Size of buffer. Sufficient for using it to call DoubleToCString in
+  // from conversions.h.
+  static const int kBufferSize = 100;
+
+  UnicodeCache* unicode_constants_;
+  // Backing store used to store strings used as hashmap keys.
+  SequenceCollector<unsigned char> backing_store_;
+  HashMap map_;
+  // Buffer used for string->number->canonical string conversions.
+  char number_buffer_[kBufferSize];
+};
+
+
+// ----------------------------------------------------------------------------
+// LiteralBuffer -  Collector of chars of literals.
+
+class LiteralBuffer {
+ public:
+  LiteralBuffer() : is_one_byte_(true), position_(0), backing_store_() { }
+
+  ~LiteralBuffer() { backing_store_.Dispose(); }
+
+  INLINE(void AddChar(uint32_t code_unit)) {
+    if (position_ >= backing_store_.length()) ExpandBuffer();
+    if (is_one_byte_) {
+      if (code_unit <= unibrow::Latin1::kMaxChar) {
+        backing_store_[position_] = static_cast<byte>(code_unit);
+        position_ += kOneByteSize;
+        return;
+      }
+      ConvertToTwoByte();
+    }
+    if (code_unit <= unibrow::Utf16::kMaxNonSurrogateCharCode) {
+      *reinterpret_cast<uint16_t*>(&backing_store_[position_]) = code_unit;
+      position_ += kUC16Size;
+    } else {
+      *reinterpret_cast<uint16_t*>(&backing_store_[position_]) =
+          unibrow::Utf16::LeadSurrogate(code_unit);
+      position_ += kUC16Size;
+      if (position_ >= backing_store_.length()) ExpandBuffer();
+      *reinterpret_cast<uint16_t*>(&backing_store_[position_]) =
+          unibrow::Utf16::TrailSurrogate(code_unit);
+      position_ += kUC16Size;
+    }
+  }
+
+  bool is_one_byte() const { return is_one_byte_; }
+
+  bool is_contextual_keyword(Vector<const char> keyword) const {
+    return is_one_byte() && keyword.length() == position_ &&
+        (memcmp(keyword.start(), backing_store_.start(), position_) == 0);
+  }
+
+  Vector<const uint16_t> two_byte_literal() const {
+    DCHECK(!is_one_byte_);
+    DCHECK((position_ & 0x1) == 0);
+    return Vector<const uint16_t>(
+        reinterpret_cast<const uint16_t*>(backing_store_.start()),
+        position_ >> 1);
+  }
+
+  Vector<const uint8_t> one_byte_literal() const {
+    DCHECK(is_one_byte_);
+    return Vector<const uint8_t>(
+        reinterpret_cast<const uint8_t*>(backing_store_.start()),
+        position_);
+  }
+
+  int length() const {
+    return is_one_byte_ ? position_ : (position_ >> 1);
+  }
+
+  void ReduceLength(int delta) {
+    position_ -= delta * (is_one_byte_ ? kOneByteSize : kUC16Size);
+  }
+
+  void Reset() {
+    position_ = 0;
+    is_one_byte_ = true;
+  }
+
+  Handle<String> Internalize(Isolate* isolate) const;
+
+  void CopyFrom(const LiteralBuffer* other) {
+    if (other == nullptr) {
+      Reset();
+    } else {
+      is_one_byte_ = other->is_one_byte_;
+      position_ = other->position_;
+      backing_store_.Dispose();
+      backing_store_ = other->backing_store_.Clone();
+    }
+  }
+
+ private:
+  static const int kInitialCapacity = 16;
+  static const int kGrowthFactory = 4;
+  static const int kMinConversionSlack = 256;
+  static const int kMaxGrowth = 1 * MB;
+  inline int NewCapacity(int min_capacity) {
+    int capacity = Max(min_capacity, backing_store_.length());
+    int new_capacity = Min(capacity * kGrowthFactory, capacity + kMaxGrowth);
+    return new_capacity;
+  }
+
+  void ExpandBuffer() {
+    Vector<byte> new_store = Vector<byte>::New(NewCapacity(kInitialCapacity));
+    MemCopy(new_store.start(), backing_store_.start(), position_);
+    backing_store_.Dispose();
+    backing_store_ = new_store;
+  }
+
+  void ConvertToTwoByte() {
+    DCHECK(is_one_byte_);
+    Vector<byte> new_store;
+    int new_content_size = position_ * kUC16Size;
+    if (new_content_size >= backing_store_.length()) {
+      // Ensure room for all currently read code units as UC16 as well
+      // as the code unit about to be stored.
+      new_store = Vector<byte>::New(NewCapacity(new_content_size));
+    } else {
+      new_store = backing_store_;
+    }
+    uint8_t* src = backing_store_.start();
+    uint16_t* dst = reinterpret_cast<uint16_t*>(new_store.start());
+    for (int i = position_ - 1; i >= 0; i--) {
+      dst[i] = src[i];
+    }
+    if (new_store.start() != backing_store_.start()) {
+      backing_store_.Dispose();
+      backing_store_ = new_store;
+    }
+    position_ = new_content_size;
+    is_one_byte_ = false;
+  }
+
+  bool is_one_byte_;
+  int position_;
+  Vector<byte> backing_store_;
+
+  DISALLOW_COPY_AND_ASSIGN(LiteralBuffer);
+};
+
+
+// ----------------------------------------------------------------------------
+// JavaScript Scanner.
+
+class Scanner {
+ public:
+  // Scoped helper for literal recording. Automatically drops the literal
+  // if aborting the scanning before it's complete.
+  class LiteralScope {
+   public:
+    explicit LiteralScope(Scanner* self) : scanner_(self), complete_(false) {
+      scanner_->StartLiteral();
+    }
+     ~LiteralScope() {
+       if (!complete_) scanner_->DropLiteral();
+     }
+    void Complete() {
+      complete_ = true;
+    }
+
+   private:
+    Scanner* scanner_;
+    bool complete_;
+  };
+
+  // Scoped helper for a re-settable bookmark.
+  class BookmarkScope {
+   public:
+    explicit BookmarkScope(Scanner* scanner) : scanner_(scanner) {
+      DCHECK_NOT_NULL(scanner_);
+    }
+    ~BookmarkScope() { scanner_->DropBookmark(); }
+
+    bool Set() { return scanner_->SetBookmark(); }
+    void Reset() { scanner_->ResetToBookmark(); }
+    bool HasBeenSet() { return scanner_->BookmarkHasBeenSet(); }
+    bool HasBeenReset() { return scanner_->BookmarkHasBeenReset(); }
+
+   private:
+    Scanner* scanner_;
+
+    DISALLOW_COPY_AND_ASSIGN(BookmarkScope);
+  };
+
+  // Representation of an interval of source positions.
+  struct Location {
+    Location(int b, int e) : beg_pos(b), end_pos(e) { }
+    Location() : beg_pos(0), end_pos(0) { }
+
+    bool IsValid() const {
+      return beg_pos >= 0 && end_pos >= beg_pos;
+    }
+
+    static Location invalid() { return Location(-1, -1); }
+
+    int beg_pos;
+    int end_pos;
+  };
+
+  // -1 is outside of the range of any real source code.
+  static const int kNoOctalLocation = -1;
+
+  explicit Scanner(UnicodeCache* scanner_contants);
+
+  void Initialize(Utf16CharacterStream* source);
+
+  // Returns the next token and advances input.
+  Token::Value Next();
+  // Returns the token following peek()
+  Token::Value PeekAhead();
+  // Returns the current token again.
+  Token::Value current_token() { return current_.token; }
+  // Returns the location information for the current token
+  // (the token last returned by Next()).
+  Location location() const { return current_.location; }
+
+  // Similar functions for the upcoming token.
+
+  // One token look-ahead (past the token returned by Next()).
+  Token::Value peek() const { return next_.token; }
+
+  Location peek_location() const { return next_.location; }
+
+  bool literal_contains_escapes() const {
+    return LiteralContainsEscapes(current_);
+  }
+  bool next_literal_contains_escapes() const {
+    return LiteralContainsEscapes(next_);
+  }
+  bool is_literal_contextual_keyword(Vector<const char> keyword) {
+    DCHECK_NOT_NULL(current_.literal_chars);
+    return current_.literal_chars->is_contextual_keyword(keyword);
+  }
+  bool is_next_contextual_keyword(Vector<const char> keyword) {
+    DCHECK_NOT_NULL(next_.literal_chars);
+    return next_.literal_chars->is_contextual_keyword(keyword);
+  }
+
+  const AstRawString* CurrentSymbol(AstValueFactory* ast_value_factory);
+  const AstRawString* NextSymbol(AstValueFactory* ast_value_factory);
+  const AstRawString* CurrentRawSymbol(AstValueFactory* ast_value_factory);
+
+  double DoubleValue();
+  bool ContainsDot();
+  bool LiteralMatches(const char* data, int length, bool allow_escapes = true) {
+    if (is_literal_one_byte() &&
+        literal_length() == length &&
+        (allow_escapes || !literal_contains_escapes())) {
+      const char* token =
+          reinterpret_cast<const char*>(literal_one_byte_string().start());
+      return !strncmp(token, data, length);
+    }
+    return false;
+  }
+  inline bool UnescapedLiteralMatches(const char* data, int length) {
+    return LiteralMatches(data, length, false);
+  }
+
+  void IsGetOrSet(bool* is_get, bool* is_set) {
+    if (is_literal_one_byte() &&
+        literal_length() == 3 &&
+        !literal_contains_escapes()) {
+      const char* token =
+          reinterpret_cast<const char*>(literal_one_byte_string().start());
+      *is_get = strncmp(token, "get", 3) == 0;
+      *is_set = !*is_get && strncmp(token, "set", 3) == 0;
+    }
+  }
+
+  int FindSymbol(DuplicateFinder* finder, int value);
+
+  UnicodeCache* unicode_cache() { return unicode_cache_; }
+
+  // Returns the location of the last seen octal literal.
+  Location octal_position() const { return octal_pos_; }
+  void clear_octal_position() { octal_pos_ = Location::invalid(); }
+
+  // Returns the value of the last smi that was scanned.
+  int smi_value() const { return current_.smi_value_; }
+
+  // Seek forward to the given position.  This operation does not
+  // work in general, for instance when there are pushed back
+  // characters, but works for seeking forward until simple delimiter
+  // tokens, which is what it is used for.
+  void SeekForward(int pos);
+
+  // Returns true if there was a line terminator before the peek'ed token,
+  // possibly inside a multi-line comment.
+  bool HasAnyLineTerminatorBeforeNext() const {
+    return has_line_terminator_before_next_ ||
+           has_multiline_comment_before_next_;
+  }
+
+  // Scans the input as a regular expression pattern, previous
+  // character(s) must be /(=). Returns true if a pattern is scanned.
+  bool ScanRegExpPattern(bool seen_equal);
+  // Scans the input as regular expression flags. Returns the flags on success.
+  Maybe<RegExp::Flags> ScanRegExpFlags();
+
+  // Scans the input as a template literal
+  Token::Value ScanTemplateStart();
+  Token::Value ScanTemplateContinuation();
+
+  const LiteralBuffer* source_url() const { return &source_url_; }
+  const LiteralBuffer* source_mapping_url() const {
+    return &source_mapping_url_;
+  }
+
+  bool IdentifierIsFutureStrictReserved(const AstRawString* string) const;
+
+ private:
+  // The current and look-ahead token.
+  struct TokenDesc {
+    Token::Value token;
+    Location location;
+    LiteralBuffer* literal_chars;
+    LiteralBuffer* raw_literal_chars;
+    int smi_value_;
+  };
+
+  static const int kCharacterLookaheadBufferSize = 1;
+
+  // Scans octal escape sequence. Also accepts "\0" decimal escape sequence.
+  template <bool capture_raw>
+  uc32 ScanOctalEscape(uc32 c, int length);
+
+  // Call this after setting source_ to the input.
+  void Init() {
+    // Set c0_ (one character ahead)
+    STATIC_ASSERT(kCharacterLookaheadBufferSize == 1);
+    Advance();
+    // Initialize current_ to not refer to a literal.
+    current_.literal_chars = NULL;
+    current_.raw_literal_chars = NULL;
+    next_next_.token = Token::UNINITIALIZED;
+  }
+
+  // Support BookmarkScope functionality.
+  bool SetBookmark();
+  void ResetToBookmark();
+  bool BookmarkHasBeenSet();
+  bool BookmarkHasBeenReset();
+  void DropBookmark();
+  static void CopyTokenDesc(TokenDesc* to, TokenDesc* from);
+
+  // Literal buffer support
+  inline void StartLiteral() {
+    LiteralBuffer* free_buffer =
+        (current_.literal_chars == &literal_buffer0_)
+            ? &literal_buffer1_
+            : (current_.literal_chars == &literal_buffer1_) ? &literal_buffer2_
+                                                            : &literal_buffer0_;
+    free_buffer->Reset();
+    next_.literal_chars = free_buffer;
+  }
+
+  inline void StartRawLiteral() {
+    LiteralBuffer* free_buffer =
+        (current_.raw_literal_chars == &raw_literal_buffer0_)
+            ? &raw_literal_buffer1_
+            : (current_.raw_literal_chars == &raw_literal_buffer1_)
+                  ? &raw_literal_buffer2_
+                  : &raw_literal_buffer0_;
+    free_buffer->Reset();
+    next_.raw_literal_chars = free_buffer;
+  }
+
+  INLINE(void AddLiteralChar(uc32 c)) {
+    DCHECK_NOT_NULL(next_.literal_chars);
+    next_.literal_chars->AddChar(c);
+  }
+
+  INLINE(void AddRawLiteralChar(uc32 c)) {
+    DCHECK_NOT_NULL(next_.raw_literal_chars);
+    next_.raw_literal_chars->AddChar(c);
+  }
+
+  INLINE(void ReduceRawLiteralLength(int delta)) {
+    DCHECK_NOT_NULL(next_.raw_literal_chars);
+    next_.raw_literal_chars->ReduceLength(delta);
+  }
+
+  // Stops scanning of a literal and drop the collected characters,
+  // e.g., due to an encountered error.
+  inline void DropLiteral() {
+    next_.literal_chars = NULL;
+    next_.raw_literal_chars = NULL;
+  }
+
+  inline void AddLiteralCharAdvance() {
+    AddLiteralChar(c0_);
+    Advance();
+  }
+
+  // Low-level scanning support.
+  template <bool capture_raw = false, bool check_surrogate = true>
+  void Advance() {
+    if (capture_raw) {
+      AddRawLiteralChar(c0_);
+    }
+    c0_ = source_->Advance();
+    if (check_surrogate) HandleLeadSurrogate();
+  }
+
+  void HandleLeadSurrogate() {
+    if (unibrow::Utf16::IsLeadSurrogate(c0_)) {
+      uc32 c1 = source_->Advance();
+      if (!unibrow::Utf16::IsTrailSurrogate(c1)) {
+        source_->PushBack(c1);
+      } else {
+        c0_ = unibrow::Utf16::CombineSurrogatePair(c0_, c1);
+      }
+    }
+  }
+
+  void PushBack(uc32 ch) {
+    if (ch > static_cast<uc32>(unibrow::Utf16::kMaxNonSurrogateCharCode)) {
+      source_->PushBack(unibrow::Utf16::TrailSurrogate(c0_));
+      source_->PushBack(unibrow::Utf16::LeadSurrogate(c0_));
+    } else {
+      source_->PushBack(c0_);
+    }
+    c0_ = ch;
+  }
+
+  inline Token::Value Select(Token::Value tok) {
+    Advance();
+    return tok;
+  }
+
+  inline Token::Value Select(uc32 next, Token::Value then, Token::Value else_) {
+    Advance();
+    if (c0_ == next) {
+      Advance();
+      return then;
+    } else {
+      return else_;
+    }
+  }
+
+  // Returns the literal string, if any, for the current token (the
+  // token last returned by Next()). The string is 0-terminated.
+  // Literal strings are collected for identifiers, strings, numbers as well
+  // as for template literals. For template literals we also collect the raw
+  // form.
+  // These functions only give the correct result if the literal was scanned
+  // when a LiteralScope object is alive.
+  Vector<const uint8_t> literal_one_byte_string() {
+    DCHECK_NOT_NULL(current_.literal_chars);
+    return current_.literal_chars->one_byte_literal();
+  }
+  Vector<const uint16_t> literal_two_byte_string() {
+    DCHECK_NOT_NULL(current_.literal_chars);
+    return current_.literal_chars->two_byte_literal();
+  }
+  bool is_literal_one_byte() {
+    DCHECK_NOT_NULL(current_.literal_chars);
+    return current_.literal_chars->is_one_byte();
+  }
+  int literal_length() const {
+    DCHECK_NOT_NULL(current_.literal_chars);
+    return current_.literal_chars->length();
+  }
+  // Returns the literal string for the next token (the token that
+  // would be returned if Next() were called).
+  Vector<const uint8_t> next_literal_one_byte_string() {
+    DCHECK_NOT_NULL(next_.literal_chars);
+    return next_.literal_chars->one_byte_literal();
+  }
+  Vector<const uint16_t> next_literal_two_byte_string() {
+    DCHECK_NOT_NULL(next_.literal_chars);
+    return next_.literal_chars->two_byte_literal();
+  }
+  bool is_next_literal_one_byte() {
+    DCHECK_NOT_NULL(next_.literal_chars);
+    return next_.literal_chars->is_one_byte();
+  }
+  Vector<const uint8_t> raw_literal_one_byte_string() {
+    DCHECK_NOT_NULL(current_.raw_literal_chars);
+    return current_.raw_literal_chars->one_byte_literal();
+  }
+  Vector<const uint16_t> raw_literal_two_byte_string() {
+    DCHECK_NOT_NULL(current_.raw_literal_chars);
+    return current_.raw_literal_chars->two_byte_literal();
+  }
+  bool is_raw_literal_one_byte() {
+    DCHECK_NOT_NULL(current_.raw_literal_chars);
+    return current_.raw_literal_chars->is_one_byte();
+  }
+
+  template <bool capture_raw>
+  uc32 ScanHexNumber(int expected_length);
+  // Scan a number of any length but not bigger than max_value. For example, the
+  // number can be 000000001, so it's very long in characters but its value is
+  // small.
+  template <bool capture_raw>
+  uc32 ScanUnlimitedLengthHexNumber(int max_value);
+
+  // Scans a single JavaScript token.
+  void Scan();
+
+  bool SkipWhiteSpace();
+  Token::Value SkipSingleLineComment();
+  Token::Value SkipSourceURLComment();
+  void TryToParseSourceURLComment();
+  Token::Value SkipMultiLineComment();
+  // Scans a possible HTML comment -- begins with '<!'.
+  Token::Value ScanHtmlComment();
+
+  void ScanDecimalDigits();
+  Token::Value ScanNumber(bool seen_period);
+  Token::Value ScanIdentifierOrKeyword();
+  Token::Value ScanIdentifierSuffix(LiteralScope* literal, bool escaped);
+
+  Token::Value ScanString();
+
+  // Scans an escape-sequence which is part of a string and adds the
+  // decoded character to the current literal. Returns true if a pattern
+  // is scanned.
+  template <bool capture_raw, bool in_template_literal>
+  bool ScanEscape();
+
+  // Decodes a Unicode escape-sequence which is part of an identifier.
+  // If the escape sequence cannot be decoded the result is kBadChar.
+  uc32 ScanIdentifierUnicodeEscape();
+  // Helper for the above functions.
+  template <bool capture_raw>
+  uc32 ScanUnicodeEscape();
+
+  Token::Value ScanTemplateSpan();
+
+  // Return the current source position.
+  int source_pos() {
+    return static_cast<int>(source_->pos()) - kCharacterLookaheadBufferSize;
+  }
+
+  static bool LiteralContainsEscapes(const TokenDesc& token) {
+    Location location = token.location;
+    int source_length = (location.end_pos - location.beg_pos);
+    if (token.token == Token::STRING) {
+      // Subtract delimiters.
+      source_length -= 2;
+    }
+    return token.literal_chars->length() != source_length;
+  }
+
+  UnicodeCache* unicode_cache_;
+
+  // Buffers collecting literal strings, numbers, etc.
+  LiteralBuffer literal_buffer0_;
+  LiteralBuffer literal_buffer1_;
+  LiteralBuffer literal_buffer2_;
+
+  // Values parsed from magic comments.
+  LiteralBuffer source_url_;
+  LiteralBuffer source_mapping_url_;
+
+  // Buffer to store raw string values
+  LiteralBuffer raw_literal_buffer0_;
+  LiteralBuffer raw_literal_buffer1_;
+  LiteralBuffer raw_literal_buffer2_;
+
+  TokenDesc current_;    // desc for current token (as returned by Next())
+  TokenDesc next_;       // desc for next token (one token look-ahead)
+  TokenDesc next_next_;  // desc for the token after next (after PeakAhead())
+
+  // Variables for Scanner::BookmarkScope and the *Bookmark implementation.
+  // These variables contain the scanner state when a bookmark is set.
+  //
+  // We will use bookmark_c0_ as a 'control' variable, where:
+  // - bookmark_c0_ >= 0: A bookmark has been set and this contains c0_.
+  // - bookmark_c0_ == -1: No bookmark has been set.
+  // - bookmark_c0_ == -2: The bookmark has been applied (ResetToBookmark).
+  //
+  // Which state is being bookmarked? The parser state is distributed over
+  // several variables, roughly like this:
+  //   ...    1234        +       5678 ..... [character stream]
+  //       [current_] [next_] c0_ |      [scanner state]
+  // So when the scanner is logically at the beginning of an expression
+  // like "1234 + 4567", then:
+  // - current_ contains "1234"
+  // - next_ contains "+"
+  // - c0_ contains ' ' (the space between "+" and "5678",
+  // - the source_ character stream points to the beginning of "5678".
+  // To be able to restore this state, we will keep copies of current_, next_,
+  // and c0_; we'll ask the stream to bookmark itself, and we'll copy the
+  // contents of current_'s and next_'s literal buffers to bookmark_*_literal_.
+  static const uc32 kNoBookmark = -1;
+  static const uc32 kBookmarkWasApplied = -2;
+  uc32 bookmark_c0_;
+  TokenDesc bookmark_current_;
+  TokenDesc bookmark_next_;
+  LiteralBuffer bookmark_current_literal_;
+  LiteralBuffer bookmark_current_raw_literal_;
+  LiteralBuffer bookmark_next_literal_;
+  LiteralBuffer bookmark_next_raw_literal_;
+
+  // Input stream. Must be initialized to an Utf16CharacterStream.
+  Utf16CharacterStream* source_;
+
+
+  // Start position of the octal literal last scanned.
+  Location octal_pos_;
+
+  // One Unicode character look-ahead; c0_ < 0 at the end of the input.
+  uc32 c0_;
+
+  // Whether there is a line terminator whitespace character after
+  // the current token, and  before the next. Does not count newlines
+  // inside multiline comments.
+  bool has_line_terminator_before_next_;
+  // Whether there is a multi-line comment that contains a
+  // line-terminator after the current token, and before the next.
+  bool has_multiline_comment_before_next_;
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_PARSING_SCANNER_H_