Update to support analyzer version 0.28.0.

[email protected]

Review URL: https://codereview.chromium.org//2287153002 .

Author: stereotype441

lib/src/dart_sdk.dart

@@ -15,6 +15,7 @@ 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:analyzer/src/summary/idl.dart';
 import 'package:cli_util/cli_util.dart' as cli_util;
 
 /// Attempts to provide the current Dart SDK directory.
@@ -173,6 +174,9 @@ class MockDartSdk implements DartSdk {
   Source fromFileUri(Uri uri) {
     throw new UnsupportedError('MockDartSdk.fromFileUri');
   }
+
+  @override
+  PackageBundle getLinkedBundle() => null;
 }
 
 class _MockSdkSource implements UriAnnotatedSource {

pubspec.yaml

@@ -6,7 +6,7 @@ homepage: https://github.com/dart-lang/code-transformers
 environment:
   sdk: '>=1.0.0 <2.0.0'
 dependencies:
-  analyzer: '>=0.27.3-alpha.7 <0.28.0'
+  analyzer: '>=0.27.3-alpha.7 <0.29.0'
   barback: '>=0.14.2 <0.16.0'
   cli_util: '>=0.0.1 <0.1.0'
   path: '>=0.9.0 <2.0.0'