Elements. Migrate analyzer/test/util/id_testing_helper.dart

Change-Id: Ie92edb3e7fb084f2d46da79d7a52fff33553a539
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/406342
Reviewed-by: Phil Quitslund <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/test/util/id_testing_helper.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// ignore_for_file: analyzer_use_new_elements
-
 // TODO(johnniwinther): .
 // TODO(paulberry): Use the code for extraction of test data from
 // annotated code from CFE.
@@ -270,12 +268,6 @@ class AnalyzerCompiledData<T> extends CompiledData<T> {
         }
       }
       return 0;
-    } else if (id is LibraryId) {
-      var unit =
-          parseString(content: code[uri]!.sourceCode, throwIfDiagnostics: false)
-              .unit;
-      var offset = unit.declaredElement?.library.nameOffset ?? -1;
-      return offset >= 0 ? offset : 0;
     } else {
       throw StateError('Unexpected id ${id.runtimeType}');
     }