<!--  As an open source project with a dedicated but small maintainer team, it can sometimes take a long time for issues to be addressed so please be patient and we will get back to you as soon as we can.
-->

### Preflight Checklist
<!-- Please ensure you've completed the following steps by replacing [ ] with [x]-->

* [x] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
* [x] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
* [x] I have searched the issue tracker for an issue that matches the one I want to file, without success.

### Issue Details

* **Electron Version:**
  * 7.0.0-beta.3
* **Operating System:**
  * macOS 10.14.5
* **Last Known Working Electron version:**
  * 6.0.2

### Expected Behavior
Show file chooser dialog when clicking input type="file" after canceled the dialog.

### Actual Behavior
Can't show file chooser dialog when clicking input type="file" after canceled the dialog.

### To Reproduce

1. Clone and Install source code.
```sh
$ git clone https://github.com/agata/electron-quick-start.git -b bug-for-file-chooser-after-canceled
$ npm install
$ npm start || electron .
```
2. Click <input type="file"> -> Show file chooser dialog.
3. Click cancel button of the dialog -> Close the dialog
4. Click <input type="file"> again -> Can't show file chooser dialog.

### Screenshots
![bug-for-file-chooser-after-canceled](https://user-images.githubusercontent.com/40473/63176157-60916900-c080-11e9-8715-f263319f0e68.gif)

### Additional Information
WebView has same problem.
shell/browser/web_dialog_helper.cc
net::GetExtensionsForMimeType(ascii_type, &extensions);
    }
    if (extensions.size() > old_extension_size)
      valid_type_count++;
  }
  
  if (extensions.empty())
    return filters;
  filters.push_back(file_dialog::Filter());
  if (valid_type_count > 1 || (valid_type_count == 1 && description.empty()))
    description = "Custom Files";
  DCHECK(!description.empty());
  filters[0].first = description;
  for (const auto& extension : extensions) {
#if defined(OS_WIN)
    filters[0].second.push_back(base::UTF16ToASCII(extension));
#else
    filters[0].second.push_back(extension);
#endif
  }
  
  filters.push_back(file_dialog::Filter());
  filters.back().first = "All Files";
  filters.back().second.push_back("*");
  return filters;
}
}  
namespace electron {
WebDialogHelper::WebDialogHelper(NativeWindow* window, bool offscreen)