Support serialization of loadLibrary

pkg/compiler/lib/src/serialization/constant_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.constants;
 
 import '../constants/constructors.dart';
 import '../constants/expressions.dart';
 import '../dart_types.dart';
 import '../elements/elements.dart' show FieldElement;
@@ skipping 151 matching lines @@
   }
 
   @override
   void visitStringLength(
       StringLengthConstantExpression exp, ObjectEncoder encoder) {
     encoder.setConstant(Key.EXPRESSION, exp.expression);
   }
 
   @override
   void visitDeferred(DeferredConstantExpression exp, ObjectEncoder encoder) {
-    throw new UnsupportedError(
-        "ConstantSerializer.visitDeferred: ${exp.toDartText()}");
+    encoder.setElement(Key.PREFIX, exp.prefix);
+    encoder.setConstant(Key.EXPRESSION, exp.expression);
   }
 }
 
 /// Utility class for deserializing [ConstantExpression]s.
 ///
 /// This is used by the [Deserializer].
 class ConstantDeserializer {
   /// Deserializes a [ConstantExpression] from an [ObjectDecoder].
   ///
   /// The class is called from the [Deserializer] when a [ConstantExpression]
@@ skipping 76 matching lines @@
         return new UnaryConstantExpression(
             operator, decoder.getConstant(Key.EXPRESSION));
       case ConstantExpressionKind.VARIABLE:
         return new VariableConstantExpression(decoder.getElement(Key.ELEMENT));
 
       case ConstantExpressionKind.POSITIONAL_REFERENCE:
         return new PositionalArgumentReference(decoder.getInt(Key.INDEX));
       case ConstantExpressionKind.NAMED_REFERENCE:
         return new NamedArgumentReference(decoder.getString(Key.NAME));
       case ConstantExpressionKind.DEFERRED:
+        return new DeferredConstantExpression(
+            decoder.getConstant(Key.EXPRESSION),
+            decoder.getElement(Key.PREFIX));
       case ConstantExpressionKind.SYNTHETIC:
     }
     throw new UnsupportedError("Unexpected constant kind: ${kind} in $decoder");
   }
 }
 
 /// Visitor that serializes a [ConstantConstructor] by encoding it into an
 /// [ObjectEncoder].
 ///
 /// This class is called from the [ConstructorSerializer] when the [Serializer]
@@ skipping 110 matching lines @@
             readFields(), readConstructorInvocation());
       case ConstantConstructorKind.REDIRECTING_GENERATIVE:
         return new RedirectingGenerativeConstantConstructor(
             readDefaults(), readConstructorInvocation());
       case ConstantConstructorKind.REDIRECTING_FACTORY:
         return new RedirectingFactoryConstantConstructor(
             readConstructorInvocation());
     }
   }
 }