Remove more references to AnalysisContext

pkg/analysis_server/lib/src/services/dependencies/reachable_source_collector.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:collection';
-
-import 'package:analyzer/src/generated/engine.dart';
-import 'package:analyzer/src/generated/source.dart';
-import 'package:analyzer/task/dart.dart';
-
-/// Collects reachable sources.
-class ReachableSourceCollector {
-  final Map<String, List<String>> _sourceMap =
-      new HashMap<String, List<String>>();
-
-  final Source source;
-  final AnalysisContext context;
-  ReachableSourceCollector(this.source, this.context) {
-    if (source == null) {
-      throw new ArgumentError.notNull('source');
-    }
-    if (context == null) {
-      throw new ArgumentError.notNull('context');
-    }
-  }
-
-  /// Collect reachable sources.
-  Map<String, List<String>> collectSources() {
-    _addDependencies(source);
-    return _sourceMap;
-  }
-
-  void _addDependencies(Source source) {
-    String sourceUri = source.uri.toString();
-
-    // Careful not to revisit.
-    if (_sourceMap[source.uri.toString()] != null) {
-      return;
-    }
-
-    List<Source> sources = <Source>[];
-    sources.addAll(context.computeResult(source, IMPORTED_LIBRARIES));
-    sources.addAll(context.computeResult(source, EXPORTED_LIBRARIES));
-
-    _sourceMap[sourceUri] =
-        sources.map((source) => source.uri.toString()).toList();
-
-    sources.forEach((s) => _addDependencies(s));
-  }
-}