Issue 21372. "Convert into block body" and "Convert into expression body" for factory constructors.

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

Index: pkg/analysis_server/lib/src/services/correction/assist_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
index f10ebfeb158d725e35280592c709f508f2152f1e..c5db0e205b11434934679b02ff36f6c97caa7502 100644
--- a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
@@ -114,6 +114,13 @@ class AssistProcessor {
       }
     }
     {
+      ConstructorDeclaration constructor =
+          node.getAncestor((node) => node is ConstructorDeclaration);
+      if (constructor != null) {
+        return constructor.body;
+      }
+    }
+    {
       MethodDeclaration method =
           node.getAncestor((node) => node is MethodDeclaration);
       if (method != null) {