Replace computeNode() with AstProvider in search.

pkg/analyzer/lib/src/dart/analysis/ast_provider_driver.dart

Index: pkg/analyzer/lib/src/dart/analysis/ast_provider_driver.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/ast_provider_driver.dart b/pkg/analyzer/lib/src/dart/analysis/ast_provider_driver.dart
index 3bd130784ed1b7b1b130d7da42c1e20dfc78f6a6..02da9fcf8c51d1da5ba51b8691698f17ada61f4a 100644
--- a/pkg/analyzer/lib/src/dart/analysis/ast_provider_driver.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/ast_provider_driver.dart
@@ -66,7 +66,7 @@ abstract class AbstractAstProvider implements AstProvider {
     if (element is TopLevelVariableElement) {
       return nameNode.getAncestor((node) => node is VariableDeclaration);
     }
-    return null;
+    return nameNode;
   }
 
   @override