Extract ClosedWorldRefiner implementation from ClosedWorldImpl to ClosedWorldBase

tests/compiler/dart2js/memory_compiler.dart

Index: tests/compiler/dart2js/memory_compiler.dart
diff --git a/tests/compiler/dart2js/memory_compiler.dart b/tests/compiler/dart2js/memory_compiler.dart
index 400572524c5412ed1d4287bdac8747023d6b97b7..809dc999ee27f454db916daa4077f3a0c1500fdd 100644
--- a/tests/compiler/dart2js/memory_compiler.dart
+++ b/tests/compiler/dart2js/memory_compiler.dart
@@ -15,7 +15,8 @@ import 'package:compiler/compiler_new.dart'
         Diagnostic,
         PackagesDiscoveryProvider;
 import 'package:compiler/src/diagnostics/messages.dart' show Message;
-import 'package:compiler/src/elements/entities.dart' show LibraryEntity;
+import 'package:compiler/src/elements/entities.dart'
+    show LibraryEntity, MemberEntity;
 import 'package:compiler/src/enqueue.dart' show ResolutionEnqueuer;
 import 'package:compiler/src/null_compiler_output.dart' show NullCompilerOutput;
 import 'package:compiler/src/library_loader.dart' show LoadedLibraries;
@@ -183,10 +184,10 @@ CompilerImpl compilerFor(
     compiler.backend.constantCompilerTask
         .copyConstantValues(cachedCompiler.backend.constantCompilerTask);
 
-    Iterable cachedTreeElements =
+    Iterable<MemberEntity> cachedTreeElements =
         cachedCompiler.enqueuer.resolution.processedEntities;
-    cachedTreeElements.forEach((element) {
-      if (element.library.isPlatformLibrary) {
+    cachedTreeElements.forEach((MemberEntity element) {
+      if (element.library.canonicalUri.scheme == 'dart') {
         resolutionEnqueuer.registerProcessedElementInternal(element);
       }
     });