Deprecate publicly-visible properties on Style in path.

pkg/path/lib/src/style/windows.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 path.style.windows;
 
 import '../parsed_path.dart';
-import '../style.dart';
+import '../internal_style.dart';
 
 /// The style for Windows paths.
-class WindowsStyle extends Style {
+class WindowsStyle extends InternalStyle {
   WindowsStyle();
 
   final name = 'windows';
   final separator = '\\';
   final separatorPattern = new RegExp(r'[/\\]');
   final needsSeparatorPattern = new RegExp(r'[^/\\]$');
   final rootPattern = new RegExp(r'^(\\\\[^\\]+\\[^\\/]+|[a-zA-Z]:[/\\])');
   final relativeRootPattern = new RegExp(r"^[/\\](?![/\\])");
 
   String pathFromUri(Uri uri) {
@@ skipping 43 matching lines @@
       }
 
       // Get rid of the trailing "\" in "C:\" because the URI constructor will
       // add a separator on its own.
       parsed.parts.insert(0, parsed.root.replaceAll(separatorPattern, ""));
 
       return new Uri(scheme: 'file', pathSegments: parsed.parts);
     }
   }
 }