Pass CompilationUnitElement to LocalElementBuilder when building locals.

R=brianwilkerson@google.com

Change-Id: Ib3c3e7fc76e075eeb312b967948ca92b212b6cf2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/100984
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
diff --git a/pkg/analyzer/lib/src/summary2/declaration_splicer.dart b/pkg/analyzer/lib/src/summary2/declaration_splicer.dart
index 7120538..708fd87 100644
--- a/pkg/analyzer/lib/src/summary2/declaration_splicer.dart
+++ b/pkg/analyzer/lib/src/summary2/declaration_splicer.dart
@@ -35,7 +35,7 @@
   void _buildLocalElements(AstNode node) {
     var holder = ElementHolder();
 
-    var elementBuilder = LocalElementBuilder(holder, null);
+    var elementBuilder = LocalElementBuilder(holder, _unitElement);
     node.accept(elementBuilder);
 
     var element = _walker.element;