pkg/path: Add type annotations to top-level and static fields.

lib/path.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.
 
 /// A comprehensive, cross-platform path manipulation library.
 ///
 /// ## Installing ##
 ///
 /// Use [pub][] to install this package. Add the following to your
 /// `pubspec.yaml` file.
@@ skipping 36 matching lines @@
 library path;
 
 import 'src/context.dart';
 import 'src/style.dart';
 
 export 'src/context.dart' hide createInternal;
 export 'src/path_exception.dart';
 export 'src/style.dart';
 
 /// A default context for manipulating POSIX paths.
-final posix = new Context(style: Style.posix);
+final Context posix = new Context(style: Style.posix);
 
 /// A default context for manipulating Windows paths.
-final windows = new Context(style: Style.windows);
+final Context windows = new Context(style: Style.windows);
 
 /// A default context for manipulating URLs.
-final url = new Context(style: Style.url);
+final Context url = new Context(style: Style.url);
 
 /// The system path context.
 ///
 /// This differs from a context created with [new Context] in that its
 /// [Context.current] is always the current working directory, rather than being
 /// set once when the context is created.
 final Context context = createInternal();
 
 /// Returns the [Style] of the current context.
 ///
@@ skipping 298 matching lines @@
 ///
 ///     // Windows at "C:\root\path"
 ///     path.prettyUri('file:///C:/root/path/a/b.dart'); // -> r'a\b.dart'
 ///     path.prettyUri('http://dartlang.org/'); // -> 'http://dartlang.org'
 ///
 ///     // URL at "http://dartlang.org/root/path"
 ///     path.prettyUri('http://dartlang.org/root/path/a/b.dart');
 ///         // -> r'a/b.dart'
 ///     path.prettyUri('file:///root/path'); // -> 'file:///root/path'
 String prettyUri(uri) => context.prettyUri(uri);