Record Typedef reference into Kernel FunctionType and resynthesyze typedefs in Analyzer.

pkg/front_end/lib/src/fasta/kernel/kernel_function_type_builder.dart

 // Copyright (c) 2017, 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 fasta.kernel_function_type_builder;
 
 import 'package:kernel/ast.dart'
     show
         DartType,
         DynamicType,
@@ skipping 19 matching lines @@
   final int charOffset;
 
   KernelFunctionTypeBuilder(
       this.charOffset,
       Uri fileUri,
       KernelTypeBuilder returnType,
       List<TypeVariableBuilder> typeVariables,
       List<FormalParameterBuilder> formals)
       : super(charOffset, fileUri, returnType, typeVariables, formals);
 
-  DartType build(LibraryBuilder library) {
+  FunctionType build(LibraryBuilder library) {
     DartType builtReturnType =
         returnType?.build(library) ?? const DynamicType();
     List<DartType> positionalParameters = <DartType>[];
     List<String> positionalParameterNames = <String>[];
     List<NamedType> namedParameters;
     int requiredParameterCount = 0;
     if (formals != null) {
       for (KernelFormalParameterBuilder formal in formals) {
         DartType type = formal.type?.build(library) ?? const DynamicType();
         if (formal.isPositional) {
@@ skipping 22 matching lines @@
         requiredParameterCount: requiredParameterCount,
         positionalParameterNames: positionalParameterNames);
   }
 
   Supertype buildSupertype(LibraryBuilder library) {
     library.addCompileTimeError(
         messageSupertypeIsFunction, charOffset, fileUri);
     return null;
   }
 }