Implement 'Import Library' Quick Fix for project libraries using TopLevelDeclarationInSource.

pkg/analyzer/lib/src/dart/analysis/top_level_declaration.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.
 
 import 'package:front_end/src/base/source.dart';
 
 /**
  * Information about a single top-level declaration.
  */
 class TopLevelDeclaration {
@@ skipping 13 matching lines @@
   /**
    * The declaring source.
    */
   final Source source;
 
   /**
    * The declaration.
    */
   final TopLevelDeclaration declaration;
 
-  TopLevelDeclarationInSource(this.source, this.declaration);
+  /**
+   * Is `true` if the [declaration] is exported, not declared in the [source].
+   */
+  final bool isExported;
+
+  TopLevelDeclarationInSource(this.source, this.declaration, this.isExported);
 
   @override
-  String toString() => '($source, $declaration)';
+  String toString() => '($source, $declaration, $isExported)';
 }
 
 /**
  * Kind of a top-level declaration.
  *
  * We don't need it to be precise, just enough to support quick fixes.
  */
 enum TopLevelDeclarationKind { type, function, variable }