Clean up warnings and hints

pkg/analyzer/lib/src/summary/incremental_cache.dart

Index: pkg/analyzer/lib/src/summary/incremental_cache.dart
diff --git a/pkg/analyzer/lib/src/summary/incremental_cache.dart b/pkg/analyzer/lib/src/summary/incremental_cache.dart
index 6370234d5bc5eebf2b84dc6bc486cae503a45b27..6b1b1aefbc191032e7e82ad8b73867a18bf661a1 100644
--- a/pkg/analyzer/lib/src/summary/incremental_cache.dart
+++ b/pkg/analyzer/lib/src/summary/incremental_cache.dart
@@ -4,7 +4,7 @@
 
 import 'dart:collection';
 import 'dart:convert';
-import 'dart:core' hide Resource;
+import 'dart:core';
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/file_system/file_system.dart';
@@ -370,6 +370,7 @@ class IncrementalCache {
           _appendLibraryClosure(closure, refSource);
         }
       }
+
       contentSource.importedUris.forEach(appendLibrarySources);
       contentSource.exportedUris.forEach(appendLibrarySources);
     }