Add toUri and fromUri functions to pathos.

pkg/stack_trace/lib/src/utils.dart

-// Copyright (c) 2013, 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 utils;
-
-import 'dart:io';
-
-import 'package:pathos/path.dart' as path;
-
-/// Converts a `file:` [Uri] to a local path string.
-String fileUriToPath(Uri uri) {
-  if (uri.scheme != 'file') {
-    throw new ArgumentError("Uri $uri must have scheme 'file:'.");
-  }
-  if (Platform.operatingSystem != 'windows') return uri.path;
-  if (uri.path.startsWith("/")) {
-    // Drive-letter paths look like "file:///C:/path/to/file". The replaceFirst
-    // removes the extra initial slash.
-    return uri.path.replaceFirst("/", "").replaceAll("/", "\\");
-  } else {
-    // Network paths look like "file://hostname/path/to/file".
-    return "\\\\${uri.path.replaceAll("/", "\\")}";
-  }
-}
-
-/// Converts a local path string to a `file:` [Uri].
-Uri pathToFileUri(String pathString) {
-  pathString = path.absolute(pathString);
-  if (Platform.operatingSystem != 'windows') {
-    return Uri.parse('file://$pathString');
-  } else if (path.rootPrefix(pathString).startsWith('\\\\')) {
-    // Network paths become "file://hostname/path/to/file".
-    return Uri.parse('file:${pathString.replaceAll("\\", "/")}');
-  } else {
-    // Drive-letter paths become "file:///C:/path/to/file".
-    return Uri.parse('file:///${pathString.replaceAll("\\", "/")}');
-  }
-}