Find native classes with mixins in NativeClassFinder

tests/compiler/dart2js/kernel/closed_world2_test.dart

Index: tests/compiler/dart2js/kernel/closed_world2_test.dart
diff --git a/tests/compiler/dart2js/kernel/closed_world2_test.dart b/tests/compiler/dart2js/kernel/closed_world2_test.dart
index ec382da99d1beb5d353f1ce98953f32af353a754..11c648ef9605c6b4439d258aba27823609efd3df 100644
--- a/tests/compiler/dart2js/kernel/closed_world2_test.dart
+++ b/tests/compiler/dart2js/kernel/closed_world2_test.dart
@@ -164,6 +164,9 @@ Future<ResultKind> mainInternal(List<String> args,
   ResolutionEnqueuer enqueuer2 = compiler2.enqueuer.resolution;
   BackendUsage backendUsage2 = compiler2.backend.backendUsage;
   ClosedWorld closedWorld2 = compiler2.resolutionWorldBuilder.closeWorld();
+
+  checkNativeClasses(compiler1, compiler2, equivalence);
+
   checkBackendUsage(backendUsage1, backendUsage2, equivalence);
 
   checkResolutionEnqueuers(backendUsage1, backendUsage2, enqueuer1, enqueuer2,
@@ -178,6 +181,25 @@ Future<ResultKind> mainInternal(List<String> args,
   return ResultKind.success;
 }
 
+void checkNativeClasses(
+    Compiler compiler1, Compiler compiler2, KernelEquivalence equivalence) {
+  Iterable<ClassEntity> nativeClasses1 = compiler1
+      .backend.nativeResolutionEnqueuerForTesting.nativeClassesForTesting;
+  Iterable<ClassEntity> nativeClasses2 = compiler2
+      .backend.nativeResolutionEnqueuerForTesting.nativeClassesForTesting;
+
+  checkSetEquivalence(compiler1, compiler2, 'nativeClasses', nativeClasses1,
+      nativeClasses2, equivalence.entityEquivalence);
+
+  Iterable<ClassEntity> registeredClasses1 = compiler1
+      .backend.nativeResolutionEnqueuerForTesting.registeredClassesForTesting;
+  Iterable<ClassEntity> registeredClasses2 = compiler2
+      .backend.nativeResolutionEnqueuerForTesting.registeredClassesForTesting;
+
+  checkSetEquivalence(compiler1, compiler2, 'registeredClasses',
+      registeredClasses1, registeredClasses2, equivalence.entityEquivalence);
+}
+
 void checkNativeBasicData(NativeBasicDataImpl data1, NativeBasicDataImpl data2,
     KernelEquivalence equivalence) {
   checkMapEquivalence(