Implement LibraryElement.hasExtUri for resynthesized.

pkg/analyzer/lib/src/dart/element/element.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.
 
 library analyzer.src.dart.element.element;
 
 import 'dart:collection';
 import 'dart:math' show min;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 5518 matching lines @@
    */
   void set exports(List<ExportElement> exports) {
     _assertNotResynthesized(_unlinkedDefiningUnit);
     for (ExportElement exportElement in exports) {
       (exportElement as ExportElementImpl).enclosingElement = this;
     }
     this._exports = exports;
   }
 
   @override
-  bool get hasExtUri => hasModifier(Modifier.HAS_EXT_URI);
+  bool get hasExtUri {
+    if (_unlinkedDefiningUnit != null) {
+      List<UnlinkedImport> unlinkedImports = _unlinkedDefiningUnit.imports;
+      for (UnlinkedImport import in unlinkedImports) {
+        if (DartUriResolver.isDartExtUri(import.uri)) {
+          return true;
+        }
+      }
+      return false;
+    }
+    return hasModifier(Modifier.HAS_EXT_URI);
+  }
 
   /**
    * Set whether this library has an import of a "dart-ext" URI.
    */
   void set hasExtUri(bool hasExtUri) {
     setModifier(Modifier.HAS_EXT_URI, hasExtUri);
   }
 
   @override
   bool get hasLoadLibraryFunction {
@@ skipping 3055 matching lines @@
 
   @override
   void visitElement(Element element) {
     int offset = element.nameOffset;
     if (offset != -1) {
       map[offset] = element;
     }
     super.visitElement(element);
   }
 }