Move library to a top-level variable, since it never changes (#887)

navigation_and_routing/lib/src/widgets/library_scope.dart

@@ -1,24 +0,0 @@
-// Copyright 2021, the Flutter 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:flutter/widgets.dart';
-
-import '../data.dart';
-
-class LibraryScope extends InheritedWidget {
-  final Library library;
-
-  const LibraryScope({
-    Key? key,
-    required this.library,
-    required Widget child,
-  }) : super(key: key, child: child);
-
-  @override
-  bool updateShouldNotify(LibraryScope oldWidget) =>
-      library != oldWidget.library;
-
-  static Library of(BuildContext context) =>
-      context.dependOnInheritedWidgetOfExactType<LibraryScope>()!.library;
-}