Elements. Use 'lookupName' in Name.

Change-Id: Ice9138ad9a47f342ac1765f7f7bb348527e5edd4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/405447
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Phil Quitslund <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart

@@ -1391,22 +1391,11 @@ class Name {
   ///
   /// If the name is a setter, the name ends with `=`.
   static Name? forElement(Element2 element) {
-    var name = element.name3;
+    var name = element.lookupName;
     if (name == null) {
       return null;
     }
 
-    // TODO(scheglov): use lookupName
-    if (element is MethodElement2 &&
-        name == '-' &&
-        element.formalParameters.isEmpty) {
-      name = 'unary-';
-    }
-
-    if (element is SetterElement) {
-      name = '$name=';
-    }
-
     if (name.startsWith('_')) {
       var libraryUri = element.firstFragment.libraryFragment!.source.uri;
       return Name(libraryUri, name);