Add import dependencies to Kernel libraries and use them to resynthesize ImportElement(s) in Analyz…

pkg/front_end/lib/src/fasta/kernel/kernel_library_builder.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 fasta.kernel_library_builder;
 
+import 'package:front_end/src/fasta/dill/dill_library_builder.dart';
+import 'package:front_end/src/fasta/import.dart';
 import 'package:kernel/ast.dart';
 
 import 'package:kernel/clone.dart' show CloneVisitor;
 
 import '../../scanner/token.dart' show Token;
 
 import '../fasta_codes.dart'
     show
         Message,
         messageConflictsWithTypeVariableCause,
@@ skipping 680 matching lines @@
       // Nothing needed.
     } else {
       unhandled("${builder.runtimeType}", "buildBuilder", builder.charOffset,
           builder.fileUri);
     }
   }
 
   @override
   Library build(LibraryBuilder coreLibrary) {
     super.build(coreLibrary);
+    for (Import import in imports) {
+      var importedBuilder = import.imported;
+      Library importedLibrary;
+      if (importedBuilder is DillLibraryBuilder) {
+        importedLibrary = importedBuilder.library;
+      } else if (importedBuilder is KernelLibraryBuilder) {
+        importedLibrary = importedBuilder.library;
+      }
+      if (importedLibrary != null) {
+        library.addDependency(
+            new LibraryDependency.import(importedLibrary, name: import.prefix));
+      }
+    }
     library.name = name;
     library.procedures.sort(compareProcedures);
     return library;
   }
 
   @override
   Builder buildAmbiguousBuilder(
       String name, Builder builder, Builder other, int charOffset,
       {bool isExport: false, bool isImport: false}) {
     // TODO(ahe): Can I move this to Scope or Prefix?
@@ skipping 153 matching lines @@
           mixinApplicationClasses.putIfAbsent(name, () => builder);
       if (existing != builder) {
         part.scope.local.remove(name);
       }
     });
     super.includePart(part);
     nativeMethods.addAll(part.nativeMethods);
     boundlessTypeVariables.addAll(part.boundlessTypeVariables);
   }
 }