Remove copies of ExportNamespaceBuilder and PublicNamespaceBuilder.

pkg/analyzer/lib/src/generated/resolver.dart

Index: pkg/analyzer/lib/src/generated/resolver.dart
diff --git a/pkg/analyzer/lib/src/generated/resolver.dart b/pkg/analyzer/lib/src/generated/resolver.dart
index e23174ebb84940eeb4f8c94fe1908702def1f517..496b821de8f7b985808eea72ca1e4ce9c9071f30 100644
--- a/pkg/analyzer/lib/src/generated/resolver.dart
+++ b/pkg/analyzer/lib/src/generated/resolver.dart
@@ -6580,14 +6580,6 @@ class NamespaceBuilder {
    */
   HashMap<String, Element> _createExportMapping(
       LibraryElement library, HashSet<LibraryElement> visitedElements) {
-    // Check if the export namespace has been already computed.
-    {
-      Namespace exportNamespace = library.exportNamespace;
-      if (exportNamespace != null) {
-        return exportNamespace.definedNames;
-      }
-    }
-    // TODO(scheglov) Remove this after switching to the new task model.
     visitedElements.add(library);
     try {
       HashMap<String, Element> definedNames = new HashMap<String, Element>();