Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

sdk/lib/_internal/compiler/implementation/scanner/string_scanner.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-part of scanner;
-
-/**
- * Scanner that reads from a String and creates tokens that points to
- * substrings.
- */
-class StringScanner extends ArrayBasedScanner {
-  /** The file content. */
-  String string;
-
-  /** The current offset in [string]. */
-  int scanOffset = -1;
-
-  StringScanner(SourceFile file, {bool includeComments: false})
-      : string = file.slowText(),
-        super(file, includeComments) {
-    ensureZeroTermination();
-  }
-
-  StringScanner.fromString(this.string, {bool includeComments: false})
-      : super(null, includeComments) {
-    ensureZeroTermination();
-  }
-
-  void ensureZeroTermination() {
-    if (string.isEmpty || string.codeUnitAt(string.length - 1) != 0) {
-      // TODO(lry): abort instead of copying the array, or warn?
-      string = string + '\x00';
-    }
-  }
-
-  int advance() => string.codeUnitAt(++scanOffset);
-  int peek() => string.codeUnitAt(scanOffset + 1);
-
-  int get stringOffset => scanOffset;
-
-  int currentAsUnicode(int next) => next;
-
-  void handleUnicode(int startScanOffset) { }
-
-  Token firstToken() => tokens.next;
-  Token previousToken() => tail;
-
-  void appendSubstringToken(PrecedenceInfo info, int start,
-                            bool asciiOnly, [int extraOffset = 0]) {
-    tail.next = new StringToken.fromSubstring(info, string, start,
-        scanOffset + extraOffset, tokenStart, canonicalize: true);
-    tail = tail.next;
-  }
-
-  bool atEndOfFile() => scanOffset >= string.length - 1;
-}