Fix for dart:html query() type inference.

pkg/analyzer/test/src/context/mock_sdk.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 analyzer.test.src.context.mock_sdk;
 
 import 'package:analyzer/file_system/file_system.dart' as resource;
 import 'package:analyzer/file_system/memory_file_system.dart' as resource;
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/context/context.dart';
@@ skipping 315 matching lines @@
     '$sdkRoot/lib/html/dart2js/html_dart2js.dart',
     '''
 library dart.html;
 class HtmlElement {}
 ''');
 
 const _MockSdkLibrary _LIB_HTML_DARTIUM = const _MockSdkLibrary(
     'dart:html',
     '$sdkRoot/lib/html/dartium/html_dartium.dart',
     '''
-library dart.html;
+library dart.dom.html;
 
-abstract class HtmlElement {}
+final HtmlDocument document;
+
+abstract class Element {}
+
+abstract class HtmlDocument {
+  Element query(String relativeSelectors) => null;
+}
+
+abstract class HtmlElement extends Element {}
+
+abstract class AnchorElement extends HtmlElement {}
+abstract class BodyElement extends HtmlElement {}
+abstract class ButtonElement extends HtmlElement {}
+abstract class DivElement extends HtmlElement {}
+abstract class InputElement extends HtmlElement {}
+abstract class SelectElement extends HtmlElement {}
+
 
 abstract class CanvasElement extends HtmlElement {
   Object getContext(String contextId, [Map attributes]);
   CanvasRenderingContext2D get context2D;
 }
 
 abstract class class CanvasRenderingContext2D {}
+
+Element query(String relativeSelectors) => null;
 ''');
 
 const _MockSdkLibrary _LIB_INTERCEPTORS = const _MockSdkLibrary(
     'dart:_interceptors',
     '$sdkRoot/lib/_internal/js_runtime/lib/interceptors.dart',
     '''
 library dart._interceptors;
 ''');
 
 const _MockSdkLibrary _LIB_MATH = const _MockSdkLibrary(
@@ skipping 251 matching lines @@
 
   @override
   AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
     if (factory == null) {
       return super.createCacheFromSourceFactory(factory);
     }
     return new AnalysisCache(
         <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
   }
 }