Add export dependencies to Kernel libraries and use them to resynthesize ExportElement(s) in Analyz…

pkg/front_end/lib/src/incremental/kernel_driver.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.
 
 import 'dart:async';
 
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/file_system.dart';
 import 'package:front_end/src/base/api_signature.dart';
 import 'package:front_end/src/base/performace_logger.dart';
@@ skipping 267 matching lines @@
       Map<Uri, FileState> uriToFile, List<DillLibraryBuilder> libraries) {
     bool wasChanged = false;
     do {
       wasChanged = false;
       for (DillLibraryBuilder library in libraries) {
         FileState file = uriToFile[library.uri];
         for (NamespaceExport export in file.exports) {
           DillLibraryBuilder exportedLibrary =
               dillTarget.loader.read(export.library.uri, -1, accessor: library);
           if (exportedLibrary != null) {
-            exportedLibrary.exports.forEach((name, member) {
+            exportedLibrary.exportScope.forEach((name, member) {
               if (export.isExposed(name) &&
                   library.addToExportScope(name, member)) {
                 wasChanged = true;
               }
             });
           } else {
             // TODO(scheglov) How to handle this?
           }
         }
       }
@@ skipping 89 matching lines @@
 
   LibraryCycleResult(this.cycle, this.signature, this.kernelLibraries);
 }
 
 @visibleForTesting
 class _TestView {
   /// The list of [LibraryCycle]s compiled for the last delta.
   /// It does not include libraries which were read from the cache.
   final List<LibraryCycle> compiledCycles = [];
 }