Files.app: Stop to use autogen IDs of TreeItems to identify tree items.

ui/file_manager/file_manager/background/js/test_util.js

Index: ui/file_manager/file_manager/background/js/test_util.js
diff --git a/ui/file_manager/file_manager/background/js/test_util.js b/ui/file_manager/file_manager/background/js/test_util.js
index 83ce6ee79dd380983b5bfb075b9808da6faa8918..d7b398bf271ec94323b99845447f952a994e921d 100644
--- a/ui/file_manager/file_manager/background/js/test_util.js
+++ b/ui/file_manager/file_manager/background/js/test_util.js
@@ -140,6 +140,24 @@ test.util.async.selectVolume = function(contentWindow, iconName, callback) {
 };
 
 /**
+ * Obtains visible tree items.
+ *
+ * @param {Window} contentWindow Window to be tested.
+ * @return {!Array<string>} List of visible item names.
+ */
+test.util.sync.getTreeItems = function(contentWindow) {
+  var items = contentWindow.document.querySelectorAll(
+      '#directory-tree .tree-item');
+  var result = [];
+  for (var i = 0; i < items.length; i++) {
+    if (items[i].matches('.tree-children:not([expanded]) *'))
+      continue;
+    result.push(items[i].querySelector('.entry-name').textContent);
+  }
+  return result;
+};
+
+/**
  * Executes Javascript code on a webview and returns the result.
  *
  * @param {Window} contentWindow Window to be tested.