switch package to strong mode

lib/src/dart_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 code_transformers.src.dart_sdk;
 
 import 'dart:io' show Directory;
 
 /// Note that the Analyzer has two versions of SdkAnalysisContext (and lots of
 /// other classes) with different signatures: can't mix the two.
-import 'package:analyzer/src/generated/engine.dart' show InternalAnalysisContext, TimestampedData;
+import 'package:analyzer/src/generated/engine.dart'
+    show InternalAnalysisContext, TimestampedData;
 import 'package:analyzer/src/context/context.dart' show SdkAnalysisContext;
 import 'package:analyzer/src/generated/java_io.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/sdk_io.dart' show DirectoryBasedDartSdk;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:cli_util/cli_util.dart' as cli_util;
 
 /// Attempts to provide the current Dart SDK directory.
 ///
 /// This will return null if the SDK cannot be found
@@ skipping 36 matching lines @@
 
   Uri restoreAbsolute(Source source) =>
       throw new UnsupportedError('restoreAbsolute is not supported');
 }
 
 /// Source file for dart: sources which track the sources with dart: URIs.
 ///
 /// This is primarily to support [Resolver.getImportUri] for Dart SDK (dart:)
 /// based libraries.
 class DartSourceProxy implements UriAnnotatedSource {
-
   /// Absolute URI which this source can be imported from
   final Uri uri;
 
   /// Underlying source object.
   final Source _proxy;
 
   Source get source => this;
 
   DartSourceProxy(this._proxy, this.uri);
 
@@ skipping 118 matching lines @@
 
   UriKind get uriKind => UriKind.DART_URI;
 
   bool get isInSystemLibrary => true;
 
   Source resolveRelative(Uri relativeUri) =>
       throw new UnsupportedError('not expecting relative urls in dart: mocks');
 
   Uri resolveRelativeUri(Uri relativeUri) =>
       throw new UnsupportedError('not expecting relative urls in dart: mocks');
+
+  bool operator ==(Object other) => identical(this, other);
 }
 
 /// Sample mock SDK sources.
 final Map<String, String> mockSdkSources = {
   // The list of types below is derived from types that are used internally by
   // the resolver (see _initializeFrom in analyzer/src/generated/resolver.dart).
   'dart:core': '''
         library dart.core;
 
         void print(Object o) {}
@@ skipping 35 matching lines @@
   'dart:async': '''
         class Future<T> {
           Future then(callback) {}
         class Stream<T> {}
   ''',
   'dart:html': '''
         library dart.html;
         class HtmlElement {}
         ''',
 };