Change Maps to HashMaps to save in performance, index and generated directories not touched

pkg/analysis_server/lib/src/package_uri_resolver.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 resolver.package;
 
+import 'dart:collection';
+
 import 'package:analysis_server/src/resource.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 
 
 /**
  * A [UriResolver] implementation for the `package:` scheme that uses a map of
  * package names to their directories.
  */
 class PackageMapUriResolver extends UriResolver {
   /**
    * The name of the `package` scheme.
    */
   static const String PACKAGE_SCHEME = "package";
 
   /**
    * A table mapping package names to the path of the directories containing
    * the package.
    */
-  final Map<String, List<Folder>> packageMap;
+  final HashMap<String, List<Folder>> packageMap;
 
   /**
    * The [ResourceProvider] for this resolver.
    */
   final ResourceProvider resourceProvider;
 
   /**
    * Create a new [PackageMapUriResolver].
    *
    * [packageMap] is a table mapping package names to the paths of the
@@ skipping 49 matching lines @@
     return new NonExistingSource(uri.toString(), UriKind.PACKAGE_URI);
   }
 
   /**
    * Returns `true` if [uri] is a `package` URI.
    */
   static bool isPackageUri(Uri uri) {
     return uri.scheme == PACKAGE_SCHEME;
   }
 }