Revert "Remove Registry from registerMetadataConstant" and "Serialize metadata"

pkg/compiler/lib/src/resolution/registry.dart

 // Copyright (c) 2014, 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 dart2js.resolution.registry;
 
 import '../common.dart';
 import '../common/backend_api.dart'
     show Backend, ForeignResolver, NativeRegistry;
 import '../common/resolution.dart'
@@ skipping 316 matching lines @@
   }
 
   //////////////////////////////////////////////////////////////////////////////
   //  Various Backend/Enqueuer/World registration.
   //////////////////////////////////////////////////////////////////////////////
 
   void registerStaticUse(StaticUse staticUse) {
     worldImpact.registerStaticUse(staticUse);
   }
 
+  void registerMetadataConstant(MetadataAnnotation metadata) {
+    backend.registerMetadataConstant(metadata, metadata.annotatedElement, this);
+  }
+
   /// Register the use of a type.
   void registerTypeUse(TypeUse typeUse) {
     worldImpact.registerTypeUse(typeUse);
   }
 
   void registerSuperUse(SourceSpan span) {
     mapping.addSuperUse(span);
   }
 
   void registerTypeLiteral(Send node, DartType type) {
@@ skipping 83 matching lines @@
   @override
   void registerInstantiatedType(InterfaceType type) {
     registry.registerInstantiation(type);
   }
 
   @override
   DartType resolveTypeFromString(Node node, String typeName) {
     return visitor.resolveTypeFromString(node, typeName);
   }
 }