Roll Observatory packages and add a roll script

analyzer/lib/src/plugin/options_plugin.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.
-
-library analyzer.src.plugin.options;
-
-import 'package:analyzer/plugin/options.dart';
-import 'package:plugin/plugin.dart';
-
-/// A plugin that defines the extension points and extensions that are defined
-/// by applications that want to consume options defined in the analysis
-/// options file.
-class OptionsPlugin implements Plugin {
-
-  /// The simple identifier of the extension point that allows plugins to
-  /// register new options processors.
-  static const String OPTIONS_PROCESSOR_EXTENSION_POINT = 'optionsProcessor';
-
-  /// The unique identifier of this plugin.
-  static const String UNIQUE_IDENTIFIER = 'options.core';
-
-  /// The extension point that allows plugins to register new options processors.
-  ExtensionPoint optionsProcessorExtensionPoint;
-
-  /// All contributed options processors.
-  List<OptionsProcessor> get optionsProcessors =>
-      optionsProcessorExtensionPoint.extensions;
-
-  @override
-  String get uniqueIdentifier => UNIQUE_IDENTIFIER;
-
-  @override
-  void registerExtensionPoints(RegisterExtensionPoint registerExtensionPoint) {
-    optionsProcessorExtensionPoint = registerExtensionPoint(
-        OPTIONS_PROCESSOR_EXTENSION_POINT, _validateOptionsProcessorExtension);
-  }
-
-  @override
-  void registerExtensions(RegisterExtension registerExtension) {
-    // There are no default extensions.
-  }
-
-  /// Validate the given extension by throwing an [ExtensionError] if it is not a
-  /// valid options processor.
-  void _validateOptionsProcessorExtension(Object extension) {
-    if (extension is! OptionsProcessor) {
-      String id = optionsProcessorExtensionPoint.uniqueIdentifier;
-      throw new ExtensionError('Extensions to $id must be an OptionsProcessor');
-    }
-  }
-}