Split backend implementation of EnqueuerListener

tests/compiler/dart2js/serialization/model_test_helper.dart

Index: tests/compiler/dart2js/serialization/model_test_helper.dart
diff --git a/tests/compiler/dart2js/serialization/model_test_helper.dart b/tests/compiler/dart2js/serialization/model_test_helper.dart
index 841ad60aef28b89d8e1ca1e46d2a21c2f1021621..8c077beab0023413f7c57157182fa603f1f23fa4 100644
--- a/tests/compiler/dart2js/serialization/model_test_helper.dart
+++ b/tests/compiler/dart2js/serialization/model_test_helper.dart
@@ -20,6 +20,7 @@ import 'package:compiler/src/elements/entities.dart';
 import 'package:compiler/src/enqueue.dart';
 import 'package:compiler/src/filenames.dart';
 import 'package:compiler/src/js_backend/js_backend.dart';
+import 'package:compiler/src/js_backend/backend_usage.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
 import 'package:compiler/src/tree/nodes.dart';
 import 'package:compiler/src/universe/class_set.dart';
@@ -97,8 +98,8 @@ Future checkModels(Uri entryPoint,
   return measure(title, 'check models', () async {
     checkAllImpacts(compilerNormal, compilerDeserialized, verbose: verbose);
     checkResolutionEnqueuers(
-        compilerNormal.backend,
-        compilerDeserialized.backend,
+        compilerNormal.backend.backendUsage,
+        compilerDeserialized.backend.backendUsage,
         compilerNormal.enqueuer.resolution,
         compilerDeserialized.enqueuer.resolution,
         verbose: verbose);
@@ -111,8 +112,8 @@ Future checkModels(Uri entryPoint,
 }
 
 void checkResolutionEnqueuers(
-    JavaScriptBackend backend1,
-    JavaScriptBackend backend2,
+    BackendUsage backendUsage1,
+    BackendUsage backendUsage2,
     ResolutionEnqueuer enqueuer1,
     ResolutionEnqueuer enqueuer2,
     {bool typeEquivalence(ResolutionDartType a, ResolutionDartType b):
@@ -152,15 +153,17 @@ void checkResolutionEnqueuers(
       "Is-check mismatch", typeEquivalence,
       verbose: verbose);
 
-  Expect.equals(backend1.hasInvokeOnSupport, backend2.hasInvokeOnSupport,
+  Expect.equals(backendUsage1.isInvokeOnUsed, backendUsage2.isInvokeOnUsed,
       "JavaScriptBackend.hasInvokeOnSupport mismatch");
   Expect.equals(
-      backend1.hasFunctionApplySupport,
-      backend2.hasFunctionApplySupport,
+      backendUsage1.isFunctionApplyUsed,
+      backendUsage1.isFunctionApplyUsed,
       "JavaScriptBackend.hasFunctionApplySupport mismatch");
-  Expect.equals(backend1.hasRuntimeTypeSupport, backend2.hasRuntimeTypeSupport,
+  Expect.equals(
+      backendUsage1.isRuntimeTypeUsed,
+      backendUsage2.isRuntimeTypeUsed,
       "JavaScriptBackend.hasRuntimeTypeSupport mismatch");
-  Expect.equals(backend1.hasIsolateSupport, backend2.hasIsolateSupport,
+  Expect.equals(backendUsage1.isIsolateInUse, backendUsage2.isIsolateInUse,
       "JavaScriptBackend.hasIsolateSupport mismatch");
 }