Files.app: Add a deduplication step to avoid importing duplicate media.

ui/file_manager/file_manager/background/js/media_import_handler_unittest.html

Index: ui/file_manager/file_manager/background/js/media_import_handler_unittest.html
diff --git a/ui/file_manager/file_manager/background/js/media_import_handler_unittest.html b/ui/file_manager/file_manager/background/js/media_import_handler_unittest.html
index d3353717e1f87f0fb5412fbc2144e3f083fa5241..834e3666d34cae59fe91f5a1c916c977f732cb35 100644
--- a/ui/file_manager/file_manager/background/js/media_import_handler_unittest.html
+++ b/ui/file_manager/file_manager/background/js/media_import_handler_unittest.html
@@ -18,6 +18,7 @@
   <script src="../../common/js/util.js"></script>
   <script src="../../common/js/volume_manager_common.js"></script>
   <script src="../../common/js/importer_common.js"></script>
+  <script src="../../common/js/test_importer_common.js"></script>
   <script src="../../common/js/progress_center_common.js"></script>
 
   <script src="test_import_history.js"></script>
@@ -26,6 +27,8 @@
   <script src="mock_volume_manager.js"></script>
   <script src="task_queue.js"></script>
   <script src="media_import_handler.js"></script>
+  <script src="duplicate_finder.js"></script>
+  <script src="test_duplicate_finder.js"></script>
   <script src="volume_manager.js"></script>
   <script src="file_operation_util.js"></script>