Avoid inserting duplicated entries after creating a directory.

ui/file_manager/file_manager/foreground/js/directory_contents.js

Index: ui/file_manager/file_manager/foreground/js/directory_contents.js
diff --git a/ui/file_manager/file_manager/foreground/js/directory_contents.js b/ui/file_manager/file_manager/foreground/js/directory_contents.js
index 5aa0678138ee08b0b6f68232d8bb6da702c7da7e..49b0d2c55c604bf2236434cdc44a80f5ef3bf873 100644
--- a/ui/file_manager/file_manager/foreground/js/directory_contents.js
+++ b/ui/file_manager/file_manager/foreground/js/directory_contents.js
@@ -824,6 +824,14 @@ DirectoryContents.prototype.onNewEntries_ = function(refresh, entries) {
   this.processNewEntriesQueue_.run(function(callbackOuter) {
     var finish = function() {
       if (!this.scanCancelled_) {
+        // Just before inserting entries into the file list, check and avoid
+        // duplication.
+        var currentURLs = {};
+        for (var i = 0; i < this.fileList_.length; i++)
+          currentURLs[this.fileList_.item(i).toURL()] = true;

[fukino, 2014/10/27 05:09:49]

This duplication check add some cost, but this doesn't change asymptotic
complexity as the following this.fileList_.push() already takes O(N), where N is
the length of the file list.

+        entriesFiltered = entriesFiltered.filter(function(entry) {
+          return !currentURLs[entry.toURL()];
+        });
         // Update the filelist without waiting the metadata.
         this.fileList_.push.apply(this.fileList_, entriesFiltered);
         cr.dispatchSimpleEvent(this, 'scan-updated');