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

pkg/compiler/lib/src/util/uri_extras.dart

-// Copyright (c) 2012, 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.
-
-library uri_extras;
-
-import 'dart:math';
-
-String relativize(Uri base, Uri uri, bool isWindows) {
-  if (!base.path.startsWith('/')) {
-    // Also throw an exception if [base] or base.path is null.
-    throw new ArgumentError('Expected absolute path: ${base.path}');
-  }
-  if (!uri.path.startsWith('/')) {
-    // Also throw an exception if [uri] or uri.path is null.
-    throw new ArgumentError('Expected absolute path: ${uri.path}');
-  }
-  bool equalsNCS(String a, String b) {
-    return a.toLowerCase() == b.toLowerCase();
-  }
-
-  String normalize(String path) {
-    if (isWindows) {
-      return path.toLowerCase();
-    } else {
-      return path;
-    }
-  }
-
-  if (equalsNCS(base.scheme, 'file') &&
-      equalsNCS(base.scheme, uri.scheme) &&
-      base.userInfo == uri.userInfo &&
-      equalsNCS(base.host, uri.host) &&
-      base.port == uri.port &&
-      uri.query == "" && uri.fragment == "") {
-    if (normalize(uri.path).startsWith(normalize(base.path))) {
-      return uri.path.substring(base.path.lastIndexOf('/') + 1);
-    }
-
-    List<String> uriParts = uri.path.split('/');
-    List<String> baseParts = base.path.split('/');
-    int common = 0;
-    int length = min(uriParts.length, baseParts.length);
-    while (common < length &&
-           normalize(uriParts[common]) == normalize(baseParts[common])) {
-      common++;
-    }
-    if (common == 1 || (isWindows && common == 2)) {
-      // The first part will always be an empty string because the
-      // paths are absolute. On Windows, we must also consider drive
-      // letters or hostnames.
-      if (baseParts.length > common + 1) {
-        // Avoid using '..' to go to the root, unless we are already there.
-        return uri.path;
-      }
-    }
-    StringBuffer sb = new StringBuffer();
-    for (int i = common + 1; i < baseParts.length; i++) {
-      sb.write('../');
-    }
-    for (int i = common; i < uriParts.length - 1; i++) {
-      sb.write('${uriParts[i]}/');
-    }
-    sb.write('${uriParts.last}');
-    return sb.toString();
-  }
-  return uri.toString();
-}