Add libraries in corrections using SourceInfo instance of LibraryElement.

pkg/analysis_server/lib/src/utilities/change_builder_dart.dart

 // Copyright (c) 2015, 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 analysis_server.src.utilities.change_builder_dart;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart' hide ElementKind;
 import 'package:analysis_server/src/provisional/edit/utilities/change_builder_core.dart';
 import 'package:analysis_server/src/provisional/edit/utilities/change_builder_dart.dart';
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
@@ skipping 440 matching lines @@
    * The compilation unit to which the code will be added.
    */
   CompilationUnit unit;
 
   /**
    * A utility class used to help build the source code.
    */
   CorrectionUtils utils;
 
   /**
-   * A set containing the elements of the libraries that need to be imported in
+   * A set containing the sources of the libraries that need to be imported in
    * order to make visible the names used in generated code.
    */
-  Set<LibraryElement> librariesToImport = new Set<LibraryElement>();
+  Set<Source> librariesToImport = new Set<Source>();
 
   /**
    * Initialize a newly created builder to build a source file edit within the
    * change being built by the given [changeBuilder]. The file being edited has
    * the given [source] and [timeStamp].
    */
   DartFileEditBuilderImpl(
       DartChangeBuilderImpl changeBuilder, Source source, int timeStamp)
       : super(changeBuilder, source, timeStamp) {
     AnalysisContext context = changeBuilder.context;
     List<Source> librariesContaining = context.getLibrariesContaining(source);
     if (librariesContaining.length < 1) {
       throw new StateError('Cannot build edits for ${source.fullName}');
     }
     unit = context.resolveCompilationUnit2(source, librariesContaining[0]);
     utils = new CorrectionUtils(unit);
   }
 
   @override
   DartEditBuilderImpl createEditBuilder(int offset, int length) {
     return new DartEditBuilderImpl(this, offset, length);
   }
 }