switch -package-root to use PackageMapUriResolver

pkg/analysis_server/lib/src/context_manager.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 context.directory.manager;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/analysis_server.dart';
@@ skipping 371 matching lines @@
   }
 
   /**
    * Compute the appropriate package URI resolver for [folder], and store
    * dependency information in [info]. Return `null` if no package map can
    * be computed.
    */
   UriResolver _computePackageUriResolver(Folder folder, _ContextInfo info) {
     if (info.packageRoot != null) {
       info.packageMapInfo = null;
+      Resource res = resourceProvider.getResource(info.packageRoot);
+      if (res is Folder) {
+        Map<String, List<Folder>> packageMap = new Map<String, List<Folder>>();
+        for (Folder folder in res.getChildren()) {
+          packageMap[folder.shortName] = <Folder>[folder];
+        }
+        return new PackageMapUriResolver(resourceProvider, packageMap);
+      }
+      //TODO(danrubel) remove this if it will never be called
       return new PackageUriResolver([new JavaFile(info.packageRoot)]);
     } else {
       beginComputePackageMap();
       OptimizingPubPackageMapInfo packageMapInfo;
       ServerPerformanceStatistics.pub.makeCurrentWhile(() {
         packageMapInfo =
             _packageMapProvider.computePackageMap(folder, info.packageMapInfo);
       });
       endComputePackageMap();
       info.packageMapInfo = packageMapInfo;
@@ skipping 378 matching lines @@
     return excludes(resource.path);
   }
 
   /**
    * Returns `true` if [path] is the pubspec file of this context.
    */
   bool isPubspec(String path) {
     return path == pubspecPath;
   }
 }