Prepare for decoupling analyzer ASTs from element model.

pkg/analysis_server/lib/src/services/correction/namespace.dart

Index: pkg/analysis_server/lib/src/services/correction/namespace.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/namespace.dart b/pkg/analysis_server/lib/src/services/correction/namespace.dart
index 87c38dd1ab610244acaa94339870365814a7f5a8..41e7e724caa7360c945594d879644130d2df090b 100644
--- a/pkg/analysis_server/lib/src/services/correction/namespace.dart
+++ b/pkg/analysis_server/lib/src/services/correction/namespace.dart
@@ -5,6 +5,7 @@
 library services.src.correction.namespace;
 
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/resolution_accessors.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/resolver/scope.dart';
 
@@ -141,7 +142,7 @@ ImportElementInfo internal_getImportElementInfo(SimpleIdentifier prefixNode) {
   AstNode parent = prefixNode.parent;
   CompilationUnit unit =
       prefixNode.getAncestor((node) => node is CompilationUnit);
-  LibraryElement libraryElement = unit.element.library;
+  LibraryElement libraryElement = elementForCompilationUnit(unit).library;
   // prepare used element
   Element usedElement = null;
   if (parent is PrefixedIdentifier) {