Add public and export namespaces to LibraryElement.

pkg/analyzer/lib/task/dart.dart

Index: pkg/analyzer/lib/task/dart.dart
diff --git a/pkg/analyzer/lib/task/dart.dart b/pkg/analyzer/lib/task/dart.dart
index 7137631741e77ec8242e4055d9976fae0dd504bf..9e1285a0dd97de646d5b9e9aca2a2c11fe60dbe6 100644
--- a/pkg/analyzer/lib/task/dart.dart
+++ b/pkg/analyzer/lib/task/dart.dart
@@ -7,7 +7,6 @@ library analyzer.task.dart;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/error.dart';
-import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/task/model.dart';
@@ -106,14 +105,6 @@ final ResultDescriptor<CompilationUnit> PARSED_UNIT =
     new ResultDescriptor<CompilationUnit>('PARSED_UNIT', null);
 
 /**
- * The public [Namespace] of a library.
- *
- * The result is only available for targets representing a Dart library.
- */
-final ResultDescriptor<Namespace> PUBLIC_NAMESPACE =
-    new ResultDescriptor<Namespace>('PUBLIC_NAMESPACE', null);
-
-/**
  * The errors produced while scanning a compilation unit.
  *
  * The list will be empty if there were no errors, but will not be `null`.