Add File.readAsBytesSync/writeAsBytesSync() methods.

pkg/analyzer/lib/file_system/file_system.dart

 // Copyright (c) 2014, 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.
 
 library analyzer.file_system.file_system;
 
 import 'dart:async';
 
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/util/absolute_path.dart';
@@ skipping 14 matching lines @@
    * Throws [FileSystemException] if the file does not exist.
    */
   int get modificationStamp;
 
   /**
    * Create a new [Source] instance that serves this file.
    */
   Source createSource([Uri uri]);
 
   /**
+   * Synchronously read the entire file contents as a list of bytes.
+   * Throws a [FileSystemException] if the operation fails.
+   */
+  List<int> readAsBytesSync();
+
+  /**
    * Synchronously read the entire file contents as a [String].
    * Throws [FileSystemException] if the file does not exist.
    */
   String readAsStringSync();
+
+  /**
+   * Synchronously write a list of bytes to the file.
+   *
+   * Throws a [FileSystemException] if the operation fails.
+   */
+  void writeAsBytesSync(List<int> bytes);
 }
 
 /**
  * Base class for all file system exceptions.
  */
 class FileSystemException implements Exception {
   final String path;
   final String message;
 
   FileSystemException(this.path, this.message);
 
   @override
   String toString() => 'FileSystemException(path=$path; message=$message)';
 }
 
 /**
  * [Folder]s are [Resource]s which may contain files and/or other folders.
  */
 abstract class Folder implements Resource {
   /**
    * Watch for changes to the files inside this folder (and in any nested
    * folders, including folders reachable via links).
    */
   Stream<WatchEvent> get changes;
 
   /**
    * If the path [path] is a relative path, convert it to an absolute path
-   * by interpreting it relative to this folder.  If it is already an aboslute
+   * by interpreting it relative to this folder.  If it is already an absolute
    * path, then don't change it.
    *
    * However, regardless of whether [path] is relative or absolute, normalize
    * it by removing path components of the form '.' or '..'.
    */
   String canonicalizePath(String path);
 
   /**
    * Return `true` if absolute [path] references a resource in this folder.
    */
@@ skipping 125 matching lines @@
 
   @override
   Uri restoreAbsolute(Source source) =>
       _provider.pathContext.toUri(source.fullName);
 
   /**
    * Return `true` if the given [uri] is a `file` URI.
    */
   static bool _isFileUri(Uri uri) => uri.scheme == _FILE_SCHEME;
 }