* Output of `node_modules/.bin/electron --version`: 3.0.10, 4.0.0-beta.7
* Operating System (Platform and Version): Ubuntu 18.04
* Output of `node_modules/.bin/electron --version` on last known working Electron version (if applicable): N/A

**Expected Behavior**
When picking a file to upload, the file picker should show a preview of the file when applicable

**Actual behavior**
It does not show a preview...

Chrome shows a preview of the image (tested with 70 and 69).
![chrome](https://user-images.githubusercontent.com/103586/48838688-01b4f280-ed81-11e8-8b38-16d7cbab1f22.png)

Electron shows no preview
![electron](https://user-images.githubusercontent.com/103586/48838699-08dc0080-ed81-11e8-8611-6a199fba23f8.png)


**To Reproduce**
Nothing special, click on a file upload form element...
```html
<input type="file" />
```
Example here: https://cgi-lib.berkeley.edu/ex/fup.html
atom/browser/ui/file_dialog_gtk.cc
gtk_widget_destroy(dialog_);
    if (parent_)
      parent_->SetEnabled(true);
  }
  void SetupProperties(int properties) {
    const auto hasProp = [properties](FileDialogProperty prop) {
      return gboolean((properties & prop) != 0);
    };
    auto* file_chooser = GTK_FILE_CHOOSER(dialog());
    gtk_file_chooser_set_select_multiple(file_chooser,
                                         hasProp(FILE_DIALOG_MULTI_SELECTIONS));
    gtk_file_chooser_set_show_hidden(file_chooser,
                                     hasProp(FILE_DIALOG_SHOW_HIDDEN_FILES));
  }
  void RunAsynchronous() {
    g_signal_connect(dialog_, "delete-event",
                     G_CALLBACK(gtk_widget_hide_on_delete), NULL);
    g_signal_connect(dialog_, "response", G_CALLBACK(OnFileDialogResponseThunk),
                     this);
    gtk_widget_show_all(dialog_);
    
    
    int time = ui::X11EventSource::GetInstance()->GetTimestamp();
    gtk_window_present_with_time(GTK_WINDOW(dialog_), time);
  }
  void RunSaveAsynchronous(const SaveDialogCallback& callback) {