Make Future.value() constructor in MockSdk consistent with the actual SDK.

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 25 matching lines @@
     '''
 library dart.async;
 
 import 'dart:math';
 
 part 'stream.dart';
 
 class Future<T> {
   factory Future(computation()) => null;
   factory Future.delayed(Duration duration, [T computation()]) => null;
-  factory Future.value([T value]) => null;
+  factory Future.value([value]) => null;
 
   static Future<List/*<T>*/> wait/*<T>*/(
       Iterable<Future/*<T>*/> futures) => null;
   Future/*<R>*/ then/*<R>*/(onValue(T value)) => null;
 
   Future<T> whenComplete(action());
 }
 
 class FutureOr<T> {}
 
@@ skipping 384 matching lines @@
       } else {
         bytes = _computeLinkedBundleBytes();
       }
       _bundle = new PackageBundle.fromBuffer(bytes);
     }
     return _bundle;
   }
 
   @override
   SdkLibrary getSdkLibrary(String dartUri) {
-    // getSdkLibrary() is only used to determine whether a library is internal
-    // to the SDK.  The mock SDK doesn't have any internals, so it's safe to
-    // return null.
+    for (SdkLibrary library in _LIBRARIES) {
+      if (library.shortName == dartUri) {
+        return library;
+      }
+    }
     return null;
   }
 
   @override
   Source mapDartUri(String dartUri) {
     String path = uriMap[dartUri];
     if (path != null) {
       resource.File file = provider.getResource(provider.convertPath(path));
       Uri uri = new Uri(scheme: 'dart', path: dartUri.substring(5));
       return file.createSource(uri);
@@ skipping 45 matching lines @@
   @override
   bool get isDart2JsLibrary => throw new UnimplementedError();
 
   @override
   bool get isDocumented => throw new UnimplementedError();
 
   @override
   bool get isImplementation => throw new UnimplementedError();
 
   @override
-  bool get isInternal => throw new UnimplementedError();
+  bool get isInternal => shortName.startsWith('dart:_');
 
   @override
   bool get isShared => throw new UnimplementedError();
 
   @override
   bool get isVmLibrary => throw new UnimplementedError();
 }
 
 /**
  * An [AnalysisContextImpl] that only contains sources for a Dart SDK.
  */
 class _SdkAnalysisContext extends AnalysisContextImpl {
   final DartSdk sdk;
 
   _SdkAnalysisContext(this.sdk);
 
   @override
   AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
     if (factory == null) {
       return super.createCacheFromSourceFactory(factory);
     }
     return new AnalysisCache(
         <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
   }
 }