Store named parameters in sorted lists instead of using maps.

lib/binary/ast_from_binary.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 kernel.ast_from_binary;
 
 import '../ast.dart';
 import 'tag.dart';
 import 'loader.dart';
 import 'dart:convert';
 import 'package:kernel/transformations/flags.dart';
@@ skipping 798 matching lines @@
   }
 
   List<Supertype> readSupertypeList() {
     return new List<Supertype>.generate(readUInt(), (i) => readSupertype());
   }
 
   List<DartType> readDartTypeList() {
     return new List<DartType>.generate(readUInt(), (i) => readDartType());
   }
 
+  List<NamedType> readNamedTypeList() {
+    return new List<NamedType>.generate(readUInt(), (i) => readNamedType());
+  }
+
+  NamedType readNamedType() {
+    return new NamedType(readStringReference(), readDartType());
+  }
+
   DartType readDartTypeOption() {
     return readAndCheckOptionTag() ? readDartType() : null;
   }
 
   DartType readDartType() {
     int tag = readByte();
     switch (tag) {
       case Tag.BottomType:
         return const BottomType();
       case Tag.InvalidType:
         return const InvalidType();
       case Tag.DynamicType:
         return const DynamicType();
       case Tag.VoidType:
         return const VoidType();
       case Tag.InterfaceType:
         return new InterfaceType(readClassReference(), readDartTypeList());
       case Tag.SimpleInterfaceType:
         return new InterfaceType(readClassReference(), const <DartType>[]);
       case Tag.FunctionType:
         int typeParameterStackHeight = typeParameterStack.length;
         var typeParameters = readAndPushTypeParameterList();
         var requiredParameterCount = readUInt();
         var positional = readDartTypeList();
-        int namedParameterCount = readUInt();
-        var named = <String, DartType>{};
-        for (int i = 0; i < namedParameterCount; ++i) {
-          var name = readStringReference();
-          var type = readDartType();
-          named[name] = type;
-        }
+        var named = readNamedTypeList();
         var returnType = readDartType();
         typeParameterStack.length = typeParameterStackHeight;
         return new FunctionType(positional, returnType,
             typeParameters: typeParameters,
             requiredParameterCount: requiredParameterCount,
             namedParameters: named);
       case Tag.SimpleFunctionType:
         var positional = readDartTypeList();
         var returnType = readDartType();
         return new FunctionType(positional, returnType);
@@ skipping 70 matching lines @@
         isFinal: flags & 0x1 != 0,
         isConst: flags & 0x2 != 0);
   }
 
   int readOffset() {
     // Offset is saved as unsigned,
     // but actually ranges from -1 and up (thus the -1)
     return readUInt() - 1;
   }
 }