Update URI related documentation and examples.

tests/corelib/uri_file_test.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.
 
 import "package:expect/expect.dart";
 
 testFileUri() {
   final unsupported = new UnsupportedError("");
 
   var tests = [
@@ skipping 70 matching lines @@
     ["file:///absolute", "/absolute", "\\absolute"],
     ["file:///a/b", "/a/b", "\\a\\b"],
     ["file:///a/b", "/a/b", "\\a\\b"],
 
     ["file://server/a/b", "//server/a/b", "\\\\server\\a\\b"],
     ["file://server/a/b/", "//server/a/b/", "\\\\server\\a\\b\\"],
 
     ["file:///C:/", "C:/", "C:\\"],
     ["file:///C:/a/b", "C:/a/b", "C:\\a\\b"],
     ["file:///C:/a/b/", "C:/a/b/", "C:\\a\\b\\"],
+
+    ["file:///C:/xxx/yyy", "C:\\xxx\\yyy", "C:\\xxx\\yyy"],
   ];
 
   for (var test in tests) {
     Uri uri = new Uri.file(test[1], windows: true);
     Expect.equals(test[0], uri.toString());
     Expect.equals(test[2], uri.toFilePath(windows: true));
     bool couldBeDir = uri.path.isEmpty || uri.path.endsWith('\\');
     Uri dirUri = new Uri.directory(test[1], windows: true);
     Expect.isTrue(dirUri.path.isEmpty || dirUri.path.endsWith('/'));
     if (couldBeDir) {
@@ skipping 215 matching lines @@
 main() {
   testFileUri();
   testFileUriWindowsSlash();
   testFileUriDriveLetter();
   testFileUriWindowsWin32Namespace();
   testFileUriResolve();
   testFileUriIllegalCharacters();
   testFileUriIllegalDriveLetter();
   testAdditionalComponents();
 }