Add optional FunctionType.positionalParameterNames and use them to resynthesize function-type forma…

pkg/kernel/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 'dart:convert';
 import 'dart:typed_data';
 
 import '../ast.dart';
 import '../transformations/flags.dart';
@@ skipping 1144 matching lines @@
       case Tag.SimpleInterfaceType:
         return new InterfaceType.byReference(
             readClassReference(), const <DartType>[]);
       case Tag.FunctionType:
         int typeParameterStackHeight = typeParameterStack.length;
         var typeParameters = readAndPushTypeParameterList();
         var requiredParameterCount = readUInt();
         var totalParameterCount = readUInt();
         var positional = readDartTypeList();
         var named = readNamedTypeList();
+        var positionalNames = readStringReferenceList();
         assert(positional.length + named.length == totalParameterCount);
         var returnType = readDartType();
         typeParameterStack.length = typeParameterStackHeight;
         return new FunctionType(positional, returnType,
             typeParameters: typeParameters,
             requiredParameterCount: requiredParameterCount,
-            namedParameters: named);
+            namedParameters: named,
+            positionalParameterNames: positionalNames);
       case Tag.SimpleFunctionType:
         var positional = readDartTypeList();
+        var positionalNames = readStringReferenceList();
         var returnType = readDartType();
-        return new FunctionType(positional, returnType);
+        return new FunctionType(positional, returnType,
+            positionalParameterNames: positionalNames);
       case Tag.TypeParameterType:
         int index = readUInt();
         readUInt(); // offset of parameter list in the binary.
         readUInt(); // index in the list.
         var bound = readDartTypeOption();
         return new TypeParameterType(typeParameterStack[index], bound);
       default:
         throw fail('Invalid dart type tag: $tag');
     }
   }
@@ skipping 68 matching lines @@
       ..fileOffset = offset
       ..fileEqualsOffset = fileEqualsOffset;
   }
 
   int readOffset() {
     // Offset is saved as unsigned,
     // but actually ranges from -1 and up (thus the -1)
     return readUInt() - 1;
   }
 }