Add toUri and fromUri functions to pathos.

pkg/stack_trace/lib/src/frame.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 frame;
 
 
 import 'package:pathos/path.dart' as path;
 
 import 'trace.dart';
-import 'utils.dart';
 
 final _nativeFrameRegExp = new RegExp(
     r'^#\d+\s+([^\s].*) \((.+):(\d+):(\d+)\)$');
 
 /// A single stack frame. Each frame points to a precise location in Dart code.
 class Frame {
   /// The URI of the file in which the code is located.
   ///
   /// This URI will usually have the scheme `dart`, `file`, `http`, or `https`.
   final Uri uri;
@@ skipping 17 matching lines @@
 
   /// Whether this stack frame comes from the Dart core libraries.
   bool get isCore => uri.scheme == 'dart';
 
   /// Returns a human-friendly description of the library that this stack frame
   /// comes from.
   ///
   /// This will usually be the string form of [uri], but a relative path will be
   /// used if possible.
   String get library {
-    // TODO(nweiz): handle relative URIs here as well once pathos supports that.
     if (uri.scheme != 'file') return uri.toString();
-    return path.relative(fileUriToPath(uri));
+    return path.relative(path.fromUri(uri));
   }
 
   /// Returns the name of the package this stack frame comes from, or `null` if
   /// this stack frame doesn't come from a `package:` URL.
   String get package {
     if (uri.scheme != 'package') return null;
     return uri.path.split('/').first;
   }
 
   /// A human-friendly description of the code location.
@@ skipping 27 matching lines @@
 
     var uri = Uri.parse(match[2]);
     var member = match[1].replaceAll("<anonymous closure>", "<fn>");
     return new Frame(uri, int.parse(match[3]), int.parse(match[4]), member);
   }
 
   Frame(this.uri, this.line, this.column, this.member);
 
   String toString() => '$location in $member';
 }