Update charted to 0.4.8 and roll

packages/path/lib/src/style/posix.dart

Index: packages/path/lib/src/style/posix.dart
diff --git a/packages/path/lib/src/style/posix.dart b/packages/path/lib/src/style/posix.dart
index 74aeb4c5381e2af897257934802caf34047ca499..5044d43706f2be3fc1c4a91b769969997126a223 100644
--- a/packages/path/lib/src/style/posix.dart
+++ b/packages/path/lib/src/style/posix.dart
@@ -2,8 +2,6 @@
 // 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.posix;
-
 import '../characters.dart' as chars;
 import '../parsed_path.dart';
 import '../internal_style.dart';
@@ -30,7 +28,7 @@ class PosixStyle extends InternalStyle {
   bool needsSeparator(String path) =>
       path.isNotEmpty && !isSeparator(path.codeUnitAt(path.length - 1));
 
-  int rootLength(String path) {
+  int rootLength(String path, {bool withDrive: false}) {
     if (path.isNotEmpty && isSeparator(path.codeUnitAt(0))) return 1;
     return 0;
   }