[filemanager] In Gallery, do not allow to rename files in readonly directory.

chrome/browser/resources/file_manager/js/image_editor/gallery.js

Index: chrome/browser/resources/file_manager/js/image_editor/gallery.js
===================================================================
--- chrome/browser/resources/file_manager/js/image_editor/gallery.js	(revision 137429)
+++ chrome/browser/resources/file_manager/js/image_editor/gallery.js	(working copy)
@@ -485,6 +485,10 @@
 };
 
 Gallery.prototype.onFilenameClick_ = function() {
+  // We can't rename files in readonly directory.
+  if (this.context_.readonlyDirName)
+    return;
+
   ImageUtil.setAttribute(this.filenameSpacer_, 'renaming', true);
   setTimeout(this.filenameEdit_.select.bind(this.filenameEdit_), 0);
   this.cancelFading_();