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

pkg/compiler/lib/src/js_emitter/constant_ordering.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 dart2js.js_emitter.constant_ordering;
 
 import '../constants/values.dart';
 
 import '../dart_types.dart';
 import '../elements/elements.dart' show Element, Elements, FieldElement;
@@ skipping 58 matching lines @@
   }
 
   int visitFunction(FunctionConstantValue a, FunctionConstantValue b) {
     return compareElements(a.element, b.element);
   }
 
   int visitNull(NullConstantValue a, NullConstantValue b) {
     return 0;
   }
 
-  int visitNonConstant(NonConstantValue a, NonConstantValue b) {
-    return 0;
-  }
-
   int visitInt(IntConstantValue a, IntConstantValue b) {
     return a.primitiveValue.compareTo(b.primitiveValue);
   }
 
   int visitDouble(DoubleConstantValue a, DoubleConstantValue b) {
     return a.primitiveValue.compareTo(b.primitiveValue);
   }
 
   int visitBool(BoolConstantValue a, BoolConstantValue b) {
     int aInt = a.primitiveValue ? 1 : 0;
@@ skipping 93 matching lines @@
   static const int DOUBLE = 4;
   static const int BOOL = 5;
   static const int STRING = 6;
   static const int LIST = 7;
   static const int MAP = 8;
   static const int CONSTRUCTED = 9;
   static const int TYPE = 10;
   static const int INTERCEPTOR = 11;
   static const int SYNTHETIC = 12;
   static const int DEFERRED = 13;
-  static const int NONCONSTANT = 13;
 
   static int kind(ConstantValue constant) =>
       constant.accept(const _KindVisitor(), null);
 
   int visitFunction(FunctionConstantValue a, _) => FUNCTION;
   int visitNull(NullConstantValue a, _) => NULL;
-  int visitNonConstant(NonConstantValue a, _) => NONCONSTANT;
   int visitInt(IntConstantValue a, _) => INT;
   int visitDouble(DoubleConstantValue a, _) => DOUBLE;
   int visitBool(BoolConstantValue a, _) => BOOL;
   int visitString(StringConstantValue a, _) => STRING;
   int visitList(ListConstantValue a, _) => LIST;
   int visitMap(MapConstantValue a, _) => MAP;
   int visitConstructed(ConstructedConstantValue a, _) => CONSTRUCTED;
   int visitType(TypeConstantValue a, _) => TYPE;
   int visitInterceptor(InterceptorConstantValue a, _) => INTERCEPTOR;
   int visitSynthetic(SyntheticConstantValue a, _) => SYNTHETIC;
   int visitDeferred(DeferredConstantValue a, _) => DEFERRED;
 }