Support multiple serialization sources in DeserializerSystemImpl.

pkg/compiler/lib/src/serialization/serialization.dart

 // Copyright (c) 2015, 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.serialization;
 
 import '../elements/elements.dart';
 import '../constants/expressions.dart';
 import '../dart_types.dart';
 import '../util/enumset.dart';
@@ skipping 862 matching lines @@
   void onElement(Element element, ObjectDecoder getDecoder(String tag)) {}
 
   /// Called to deserialize custom data from [decoder].
   dynamic onData(ObjectDecoder decoder) {}
 }
 
 /// Context for parallel deserialization.
 class DeserializationContext {
   Map<Uri, LibraryElement> _uriMap = <Uri, LibraryElement>{};
   List<Deserializer> deserializers = <Deserializer>[];
+  List<DeserializerPlugin> plugins = <DeserializerPlugin>[];
 
   LibraryElement lookupLibrary(Uri uri) {
     return _uriMap.putIfAbsent(uri, () {
       for (Deserializer deserializer in deserializers) {
         LibraryElement library = deserializer.lookupLibrary(uri);
         if (library != null) {
           return library;
         }
       }
       return null;
     });
   }
 }
 
 /// Deserializer for a closed collection of libraries.
 // TODO(johnniwinther): Support per-library deserialization and dependencies
 // between deserialized subcomponent.
 class Deserializer {
   final DeserializationContext context;
   final SerializationDecoder decoder;
-  List<DeserializerPlugin> plugins = <DeserializerPlugin>[];
   ObjectDecoder _headerObject;
   ListDecoder _elementList;
   ListDecoder _typeList;
   ListDecoder _constantList;
   Map<int, Element> _elementMap = {};
   Map<int, DartType> _typeMap = {};
   Map<int, ConstantExpression> _constantMap = {};
 
   Deserializer.fromText(this.context, String text, this.decoder) {
     _headerObject = new ObjectDecoder(this, decoder.decode(text));
-    context.deserializers.add(this);
   }
 
   /// Returns the [ListDecoder] for the [Element]s in this deserializer.
   ListDecoder get elements {
     if (_elementList == null) {
       _elementList = _headerObject.getList(Key.ELEMENTS);
     }
     return _elementList;
   }
 
@@ skipping 68 matching lines @@
           throw new StateError("Missing constructor for $name in $cls.");
         }
       } else {
         element = ElementDeserializer.deserialize(decoder, elementKind);
       }
       _elementMap[id] = element;
 
       MapDecoder pluginData = decoder.getMap(Key.DATA, isOptional: true);
       // Call plugins even when there is no data, so they can take action in
       // this case.
-      for (DeserializerPlugin plugin in plugins) {
+      for (DeserializerPlugin plugin in context.plugins) {
         plugin.onElement(element,
             (String tag) => pluginData?.getObject(tag, isOptional: true));
       }
     }
     return element;
   }
 
   /// Returns the deserialized [DartType] for [id].
   DartType deserializeType(int id) {
     if (id == null) throw new ArgumentError('Deserializer.getType(null)');
@@ skipping 26 matching lines @@
 
   /// Returns the value used to store [key] as a property in the encoding an
   /// [ObjectValue].
   ///
   /// Different encodings have different restrictions and capabilities as how
   /// to store a [Key] value. For instance: A JSON encoding needs to convert
   /// [Key] to a [String] to store it in a JSON object; a Dart encoding can
   /// choose to store a [Key] as an [int] or as the [Key] itself.
   getObjectPropertyValue(Key key);
 }