Remove UriReferencedElement with its uri/uriOffset/uriEnd properties.

pkg/analysis_server/test/services/completion/dart/completion_manager_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 import 'dart:async';
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart';
@@ skipping 49 matching lines @@
       requestCompleter.complete(request);
     });
     request = await performAnalysis(200, requestCompleter);
 
     var directives = request.target.unit.directives;
 
     List<ImportElement> imports = request.libraryElement.imports;
     expect(imports, hasLength(directives.length + 1));
 
     ImportElement importNamed(String expectedUri) {
-      return imports.firstWhere((elem) => elem.uri == expectedUri, orElse: () {
-        var importedNames = imports.map((elem) => elem.uri);
-        fail('Failed to find $expectedUri in $importedNames');
-      });
+      List<String> uriList = <String>[];
+      for (ImportElement importElement in imports) {
+        String uri = importElement.importedLibrary.source.uri.toString();
+        uriList.add(uri);
+        if (uri.endsWith(expectedUri)) {
+          return importElement;
+        }
+      }
+      fail('Failed to find $expectedUri in $uriList');
+      return null;
     }
 
     void assertImportedLib(String expectedUri) {
       ImportElement importElem = importNamed(expectedUri);
       expect(importElem.importedLibrary.exportNamespace, isNotNull);
     }
 
     // Assert that the new imports each have an export namespace
-    assertImportedLib(null /* dart:core */);
-    assertImportedLib('/libA.dart');
+    assertImportedLib('dart:core');
+    assertImportedLib('libA.dart');
   }
 }