Remove Resource class and support functions.

tests/corelib/file_resource_test.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.
-
-import "dart:io";
-
-const sampleText = "Sample text file.";
-
-main() async {
-  var file = await createFile();
-  var uri = new Uri.file(file.path);
-
-  var resource = new Resource(uri.toString());
-
-  if (resource.uri != uri) {
-    throw "Incorrect URI: ${resource.uri}";
-  }
-
-  var text = await resource.readAsString();
-  if (text != sampleText) {
-    throw "Incorrect reading of text file: $text";
-  }
-
-  var bytes = await resource.readAsBytes();
-  if (!compareBytes(bytes, sampleText.codeUnits)) {
-    throw "Incorrect reading of bytes: $bytes";
-  }
-
-  var streamBytes = [];
-  await for (var byteSlice in resource.openRead()) {
-    streamBytes.addAll(byteSlice);
-  }
-  if (!compareBytes(streamBytes, sampleText.codeUnits)) {
-    throw "Incorrect reading of bytes: $bytes";
-  }
-
-  await deleteFile(file);
-}
-
-/// Checks that [bytes] and [expectedBytes] have the same contents.
-bool compareBytes(bytes, expectedBytes) {
-  if (bytes.length != expectedBytes.length) return false;
-  for (int i = 0; i < expectedBytes.length; i++) {
-    if (bytes[i] != expectedBytes[i]) return false;
-  }
-  return true;
-}
-
-createFile() async {
-  var tempDir = await Directory.systemTemp.createTemp("sample");
-  var filePath = tempDir.path + Platform.pathSeparator + "sample.txt";
-  var file = new File(filePath);
-  await file.create();
-  await file.writeAsString(sampleText);
-  return file;
-}
-
-deleteFile(File file) async {
-  // Removes the file and the temporary directory it's in.
-  var parentDir = new Directory(file.path.substring(0,
-                                file.path.lastIndexOf(Platform.pathSeparator)));
-  await parentDir.delete(recursive: true);
-}