Revert "Add Resource class. Currently unimplemented."

sdk/lib/core/resource.dart

-// Copyright (c) 2015, 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.
-
-part of dart.core;
-
-/**
- * A resource that can be read into the program.
- *
- * A resource is data that can be located using a URI and read into
- * the program at runtime.
- * The URI may use the `package` scheme to read resources provided
- * along with package sources.
- */
-abstract class Resource {
-  /**
-   * Creates a resource object with the given [uri] as location.
-   *
-   * The `uri` is a string containing a valid URI.
-   * If the string is not a valid URI, using any of the functions on
-   * the resource object will fail.
-   *
-   * The URI may be relative, in which case it will be resolved
-   * against [Uri.base] before being used.
-   *
-   * The URI may use the `package` scheme, which is always supported.
-   * Other schemes may also be supported where possible.
-   */
-  external const factory Resource(String uri);
-
-  /**
-   * The location `uri` of this resource.
-   *
-   * This is a [Uri] of the `uri` parameter given to the constructor.
-   * If the parameter was not a valid URI, reading `uri` may fail.
-   */
-  Uri get uri;
-
-  /** Read the resource content as a stream of bytes. */
-  Stream<List<int>> openRead();
-
-  /** Read the resource content. */
-  Future<List<int>> readAsBytes();
-
-  /**
-   * Read the resource content as a string.
-   *
-   * The content is decoded into a string using an [Encoding].
-   * If no other encoding is provided, it defaults to UTF-8.
-   */
-  Future<String> readAsString({Encoding encoding});
-}