* 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
#include "atom/browser/ui/file_dialog.h"
#include <glib/gi18n.h>  
#include "atom/browser/native_window_views.h"
#include "atom/browser/unresponsive_suppressor.h"
#include "base/callback.h"
#include "base/files/file_util.h"
#include "base/strings/string_util.h"
#include "chrome/browser/ui/libgtkui/gtk_util.h"
#include "ui/base/glib/glib_signal.h"
#include "ui/views/widget/desktop_aura/x11_desktop_handler.h"
namespace file_dialog {
DialogSettings::DialogSettings() = default;
DialogSettings::DialogSettings(const DialogSettings&) = default;
DialogSettings::~DialogSettings() = default;
namespace {
gboolean FileFilterCaseInsensitive(const GtkFileFilterInfo* file_info,
                                   std::string* file_extension) {
  
  if (*file_extension == ".*")
    return true;
  return base::EndsWith(file_info->filename, *file_extension,
                        base::CompareCase::INSENSITIVE_ASCII);
}
void OnFileFilterDataDestroyed(std::string* file_extension) {
  delete file_extension;
}
class FileChooserDialog {