Suppress follow-on errors when a file is imported with either a prefix or a show clause

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 280 matching lines @@
     "dart:collection": "/lib/collection/collection.dart",
     "dart:convert": "/lib/convert/convert.dart",
     "dart:_foreign_helper": "/lib/_foreign_helper/_foreign_helper.dart",
     "dart:math": "/lib/math/math.dart"
   };
 
   static const Map<String, String> NO_ASYNC_URI_MAP = const {
     "dart:core": "/lib/core/core.dart",
   };
 
-  final resource.MemoryResourceProvider provider =
-      new resource.MemoryResourceProvider();
+  final resource.MemoryResourceProvider provider;
 
   final Map<String, String> uriMap;
 
   /**
    * The [AnalysisContextImpl] which is used for all of the sources.
    */
   AnalysisContextImpl _analysisContext;
 
   @override
   final List<SdkLibrary> sdkLibraries;
 
-  MockSdk({bool dartAsync: true})
-      : sdkLibraries = dartAsync ? _LIBRARIES : [_LIB_CORE],
+  MockSdk({bool dartAsync: true, resource.ResourceProvider resourceProvider})
+      : provider = resourceProvider ?? new resource.MemoryResourceProvider(),
+        sdkLibraries = dartAsync ? _LIBRARIES : [_LIB_CORE],
         uriMap = dartAsync ? FULL_URI_MAP : NO_ASYNC_URI_MAP {
     for (_MockSdkLibrary library in sdkLibraries) {
       provider.newFile(library.path, library.content);
       library.parts.forEach((String path, String content) {
         provider.newFile(path, content);
       });
     }
   }
 
   @override
@@ skipping 110 matching lines @@
 
   @override
   AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
     if (factory == null) {
       return super.createCacheFromSourceFactory(factory);
     }
     return new AnalysisCache(
         <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
   }
 }