Fix hints reported by analyzer.

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

 // Copyright (c) 2016, 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.util;
 
 import '../common.dart';
 import '../constants/expressions.dart';
 import '../elements/resolution_types.dart';
 import '../diagnostics/messages.dart';
@@ skipping 34 matching lines @@
       Key.NAMED_ARGUMENTS, selector.callStructure.namedArguments);
   serializeName(selector.memberName, encoder);
 }
 
 /// Deserialize a [Selector] from [decoder].
 Selector deserializeSelector(ObjectDecoder decoder) {
   SelectorKind kind = decoder.getEnum(Key.KIND, SelectorKind.values);
   int argumentCount = decoder.getInt(Key.ARGUMENTS);
   List<String> namedArguments =
       decoder.getStrings(Key.NAMED_ARGUMENTS, isOptional: true);
-  String name = decoder.getString(Key.NAME);
-  bool isSetter = decoder.getBool(Key.IS_SETTER);
-  LibraryElement library = decoder.getElement(Key.LIBRARY, isOptional: true);
   return new Selector(kind, deserializeName(decoder),
       new CallStructure(argumentCount, namedArguments));
 }
 
 /// Serialize [sendStructure] into [encoder].
 void serializeSendStructure(
     SendStructure sendStructure, ObjectEncoder encoder) {
   encoder.setEnum(Key.KIND, sendStructure.kind);
   switch (sendStructure.kind) {
     case SendStructureKind.IF_NULL:
@@ skipping 514 matching lines @@
   ObjectDecoder sourceSpanDecoder =
       object.getObject(Key.SOURCE_SPAN, isOptional: true);
   if (sourceSpanDecoder != null) {
     sourceSpan = deserializeSourceSpan(sourceSpanDecoder);
   }
   MessageKind messageKind = object.getEnum(Key.KIND, MessageKind.values);
   Map<String, dynamic> messageArguments =
       deserializeMessageArguments(object, Key.ARGUMENTS);
   return new WrappedMessage(sourceSpan, messageKind, messageArguments);
 }