Be more careful about converting between file URIs and paths.

pkg/stack_trace/test/frame_test.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_test;
 
 import 'dart:io';
 import 'dart:uri';
 
 import 'package:pathos/path.dart' as path;
+import 'package:stack_trace/src/utils.dart';
 import 'package:stack_trace/stack_trace.dart';
 import 'package:unittest/unittest.dart';
 
 String getStackFrame() {
   try {
     throw '';
   } catch (_, stackTrace) {
     return stackTrace.toString().split("\n").first;
   }
 }
@@ skipping 14 matching lines @@
     expect(frame.line, equals(42));
     expect(frame.column, equals(21));
     expect(frame.member, equals('Foo._bar'));
   });
 
   test('parses a real stack frame correctly', () {
     var frame = new Frame.parse(getStackFrame());
     // TODO(nweiz): use URL-style paths when such a thing exists.
     var builder = new path.Builder(style: path.Style.posix);
     expect(builder.basename(frame.uri.path), equals('frame_test.dart'));
-    expect(frame.line, equals(16));
+    expect(frame.line, equals(17));
     expect(frame.column, equals(5));
     expect(frame.member, equals('getStackFrame'));
   });
 
   test('converts "<anonymous closure>" to "<fn>"', () {
     String parsedMember(String member) =>
         new Frame.parse('#0 $member (foo:0:0)').member;
 
     expect(parsedMember('Foo.<anonymous closure>'), equals('Foo.<fn>'));
     expect(parsedMember('<anonymous closure>.<anonymous closure>.bar'),
@@ skipping 50 matching lines @@
   group('.library', () {
     test('returns the URI string for non-file URIs', () {
       expect(new Frame.parse('#0 Foo (dart:async:0:0)').library,
           equals('dart:async'));
       expect(new Frame.parse('#0 Foo '
               '(http://dartlang.org/stuff/thing.dart:0:0)').library,
           equals('http://dartlang.org/stuff/thing.dart'));
     });
 
     test('returns the relative path for file URIs', () {
-      var uri = _pathToFileUri(path.join('foo', 'bar.dart'));
+      var uri = pathToFileUri(path.join('foo', 'bar.dart'));
       expect(new Frame.parse('#0 Foo ($uri:0:0)').library,
           equals(path.join('foo', 'bar.dart')));
     });
   });
 
   group('.location', () {
     test('returns the library and line/column numbers for non-core '
         'libraries', () {
       expect(new Frame.parse('#0 Foo '
               '(http://dartlang.org/thing.dart:5:10)').location,
           equals('http://dartlang.org/thing.dart 5:10'));
-      var uri = _pathToFileUri(path.join('foo', 'bar.dart'));
+      var uri = pathToFileUri(path.join('foo', 'bar.dart'));
       expect(new Frame.parse('#0 Foo ($uri:1:2)').location,
           equals('${path.join('foo', 'bar.dart')} 1:2'));
     });
 
     test('just returns the library for core libraries', () {
       expect(new Frame.parse('#0 Foo (dart:core:5:10)').location,
           equals('dart:core'));
       expect(new Frame.parse('#0 Foo (dart:async-patch:1:2)').location,
           equals('dart:async-patch'));
     });
@@ skipping 12 matching lines @@
           equals('dart:core in Foo'));
     });
 
     test('converts "<anonymous closure>" to "<fn>"', () {
       expect(new Frame.parse('#0 Foo.<anonymous closure> (dart:core:5:10)')
               .toString(),
           equals('dart:core in Foo.<fn>'));
     });
   });
 }
-
-String _pathToFileUri(String pathString) {
-  pathString = path.absolute(pathString);
-  if (Platform.operatingSystem != 'windows') return 'file://$pathString';
-  return 'file:///${pathString.replaceAll("\\", "/")}';
-}