Support serialization of all resolved asts from dart:core

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 214 matching lines @@
       case ConstantExpressionKind.IDENTICAL:
         return new IdenticalConstantExpression(
             decoder.getConstant(Key.LEFT), decoder.getConstant(Key.RIGHT));
       case ConstantExpressionKind.INT:
         return new IntConstantExpression(decoder.getInt(Key.VALUE));
       case ConstantExpressionKind.INT_FROM_ENVIRONMENT:
         return new IntFromEnvironmentConstantExpression(
             decoder.getConstant(Key.NAME),
             decoder.getConstant(Key.DEFAULT, isOptional: true));
       case ConstantExpressionKind.LIST:
-        return new ListConstantExpression(
-            decoder.getType(Key.TYPE), decoder.getConstants(Key.VALUES));
+        return new ListConstantExpression(decoder.getType(Key.TYPE),
+            decoder.getConstants(Key.VALUES, isOptional: true));
       case ConstantExpressionKind.MAP:
-        return new MapConstantExpression(decoder.getType(Key.TYPE),
-            decoder.getConstants(Key.KEYS), decoder.getConstants(Key.VALUES));
+        return new MapConstantExpression(
+            decoder.getType(Key.TYPE),
+            decoder.getConstants(Key.KEYS, isOptional: true),
+            decoder.getConstants(Key.VALUES, isOptional: true));
       case ConstantExpressionKind.NULL:
         return new NullConstantExpression();
       case ConstantExpressionKind.STRING:
         return new StringConstantExpression(decoder.getString(Key.VALUE));
       case ConstantExpressionKind.STRING_FROM_ENVIRONMENT:
         return new StringFromEnvironmentConstantExpression(
             decoder.getConstant(Key.NAME),
             decoder.getConstant(Key.DEFAULT, isOptional: true));
       case ConstantExpressionKind.STRING_LENGTH:
         return new StringLengthConstantExpression(
             decoder.getConstant(Key.EXPRESSION));
       case ConstantExpressionKind.SYMBOL:
-        break;
+        return new SymbolConstantExpression(decoder.getString(Key.NAME));
       case ConstantExpressionKind.TYPE:
         return new TypeConstantExpression(decoder.getType(Key.TYPE));
       case ConstantExpressionKind.UNARY:
         UnaryOperator operator = UnaryOperator
             .fromKind(decoder.getEnum(Key.OPERATOR, UnaryOperatorKind.values));
         return new UnaryConstantExpression(
             operator, decoder.getConstant(Key.EXPRESSION));
       case ConstantExpressionKind.VARIABLE:
         return new VariableConstantExpression(decoder.getElement(Key.ELEMENT));
 
@@ skipping 125 matching lines @@
             readFields(), readConstructorInvocation());
       case ConstantConstructorKind.REDIRECTING_GENERATIVE:
         return new RedirectingGenerativeConstantConstructor(
             readDefaults(), readConstructorInvocation());
       case ConstantConstructorKind.REDIRECTING_FACTORY:
         return new RedirectingFactoryConstantConstructor(
             readConstructorInvocation());
     }
   }
 }