* chore: small memory management improvement
Co-authored-by: Charles Kerr <ckerr@github.com>
* chore: fix code style
* use start-from-one ref count, check ref_counted.h for motivations
* reuse list_base_dir_
* net::DirectorLister offloads directory enumeration to a different
task sequence in its implementation, use of sequence runner on
our end is unnecessary
* Don't manually `Release` in `WebContentsDestroyed`, content::FileSelectListener
already handles this case.