Create ResolutionEnqueuer after library loading.

pkg/compiler/lib/src/js_backend/backend.dart

 // Copyright (c) 2012, 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 js_backend.backend;
 
 import 'dart:async' show Future;
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
 
@@ skipping 813 matching lines @@
         // constant emitter will generate a call to the createRuntimeType
         // helper so we register a use of that.
         impactBuilder.registerStaticUse(new StaticUse.staticInvoke(
             // TODO(johnniwinther): Find the right [CallStructure].
             helpers.createRuntimeType,
             null));
       }
     }
   }
 
+  void onResolutionStart(ResolutionEnqueuer enqueuer) {
+    helpers.onResolutionStart();
+
+    validateInterceptorImplementsAllObjectMethods(helpers.jsInterceptorClass);
+    // The null-interceptor must also implement *all* methods.
+    validateInterceptorImplementsAllObjectMethods(helpers.jsNullClass);
+  }
+
   void onResolutionComplete(
       ClosedWorld closedWorld, ClosedWorldRefiner closedWorldRefiner) {
     for (Entity entity in compiler.enqueuer.resolution.processedEntities) {
       processAnnotations(entity, closedWorldRefiner);
     }
     mirrorsData.computeMembersNeededForReflection(
         compiler.enqueuer.resolution.worldBuilder, closedWorld);
     _backendUsage = _backendUsageBuilder.close();
     _rtiNeed = rtiNeedBuilder.computeRuntimeTypesNeed(
         compiler.enqueuer.resolution.worldBuilder,
@@ skipping 326 matching lines @@
 
     // These methods are overwritten with generated versions.
     inlineCache.markAsNonInlinable(helpers.getInterceptorMethod,
         insideLoop: true);
 
     specialOperatorEqClasses
       ..add(commonElements.objectClass)
       ..add(helpers.jsInterceptorClass)
       ..add(helpers.jsNullClass);
 
-    validateInterceptorImplementsAllObjectMethods(helpers.jsInterceptorClass);
-    // The null-interceptor must also implement *all* methods.
-    validateInterceptorImplementsAllObjectMethods(helpers.jsNullClass);
-
     return new Future.value();
   }
 
   jsAst.Call generateIsJsIndexableCall(
       jsAst.Expression use1, jsAst.Expression use2) {
     String dispatchPropertyName = embeddedNames.DISPATCH_PROPERTY_NAME;
     jsAst.Expression dispatchProperty =
         emitter.generateEmbeddedGlobalAccess(dispatchPropertyName);
 
     // We pass the dispatch property record to the isJsIndexable
@@ skipping 429 matching lines @@
     return _backend.defaultSuperclass(element);
   }
 
   @override
   bool isNativeClass(ClassEntity element) =>
       _backend.nativeClassData.isNativeClass(element);
 
   @override
   bool isForeign(Element element) => _backend.isForeign(element);
 }