Use SdkExtensionFinder in the old Analysis Server implementation.

pkg/analysis_server/lib/src/analysis_server.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 analysis.server;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core' hide Resource;
 import 'dart:io' as io;
@@ skipping 1665 matching lines @@
    * Set up a [SourceFactory] that resolves packages as appropriate for the
    * given [disposition].
    */
   SourceFactory _createSourceFactory(InternalAnalysisContext context,
       AnalysisOptions options, FolderDisposition disposition, Folder folder) {
     List<UriResolver> resolvers = [];
     List<UriResolver> packageUriResolvers =
         disposition.createPackageUriResolvers(resourceProvider);
 
     // If no embedded URI resolver was provided, defer to a locator-backed one.
+    SdkExtensionFinder extFinder =
+        disposition.getSdkExtensionFinder(resourceProvider);
+    List<String> extFilePaths = extFinder.extensionFilePaths;
     EmbedderYamlLocator locator =
         disposition.getEmbedderLocator(resourceProvider);
     Map<Folder, YamlMap> embedderYamls = locator.embedderYamls;
     EmbedderSdk embedderSdk = new EmbedderSdk(resourceProvider, embedderYamls);
     if (embedderSdk.libraryMap.size() == 0) {
       // There was no embedder file, or the file was empty, so used the default
       // SDK.
       resolvers.add(new DartUriResolver(
           analysisServer.sdkManager.getSdkForOptions(options)));
     } else {
       // The embedder file defines an alternate SDK, so use it.
       List<String> paths = <String>[];
       for (Folder folder in embedderYamls.keys) {
         paths.add(folder
             .getChildAssumingFile(EmbedderYamlLocator.EMBEDDER_FILE_NAME)
             .path);
       }
+      paths.addAll(extFilePaths);
       DartSdk dartSdk = analysisServer.sdkManager
           .getSdk(new SdkDescription(paths, options), () {
+        if (extFilePaths.isNotEmpty) {
+          embedderSdk.addExtensions(extFinder.urlMappings);
+        }
         embedderSdk.analysisOptions = options;
         // TODO(brianwilkerson) Enable summary use after we have decided where
         // summary files for embedder files will live.
         embedderSdk.useSummary = false;
         return embedderSdk;
       });
       resolvers.add(new DartUriResolver(dartSdk));
     }
 
     resolvers.addAll(packageUriResolvers);
@@ skipping 100 matching lines @@
   /**
    * The [PerformanceTag] for time spent in server request handlers.
    */
   static PerformanceTag serverRequests = new PerformanceTag('serverRequests');
 
   /**
    * The [PerformanceTag] for time spent in split store microtasks.
    */
   static PerformanceTag splitStore = new PerformanceTag('splitStore');
 }