Fix test failures on the bots

pkg/analysis_server/test/abstract_context.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 testing.abstract_context;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source_io.dart';
+import 'package:plugin/manager.dart';
 
 import 'mock_sdk.dart';
 
 /**
  * Finds an [Element] with the given [name].
  */
 Element findChildElement(Element root, String name, [ElementKind kind]) {
   Element result = null;
   root.accept(new _ElementVisitorFunctionWrapper((Element element) {
     if (element.name != name) {
@@ skipping 51 matching lines @@
 
   CompilationUnit resolveDartUnit(Source unitSource, Source librarySource) {
     return context.resolveCompilationUnit2(unitSource, librarySource);
   }
 
   CompilationUnit resolveLibraryUnit(Source source) {
     return context.resolveCompilationUnit2(source, source);
   }
 
   void setUp() {
+    ExtensionManager extensionManager = new ExtensionManager();
+    extensionManager.processPlugins(AnalysisEngine.instance.supportedPlugins);
     setupResourceProvider();
     resourceResolver = new ResourceUriResolver(provider);
     packageMap = new Map<String, List<Folder>>();
     PackageMapUriResolver packageResolver =
         new PackageMapUriResolver(provider, packageMap);
     context = AnalysisEngine.instance.createAnalysisContext();
     context.sourceFactory =
         new SourceFactory([SDK_RESOLVER, packageResolver, resourceResolver]);
   }
 
@@ skipping 12 matching lines @@
  * [engine.GeneralizingElementVisitor].
  */
 class _ElementVisitorFunctionWrapper extends GeneralizingElementVisitor {
   final _ElementVisitorFunction function;
   _ElementVisitorFunctionWrapper(this.function);
   visitElement(Element element) {
     function(element);
     super.visitElement(element);
   }
 }