Update base/extractor.[cc|h] for security review. Change-Id: I58430f3609301ec6b07610917345c958c67cc26a Reviewed-on: https://chromium-review.googlesource.com/223041 Reviewed-by: Will Harris <[email protected]> Reviewed-by: Jack Hou <[email protected]> Tested-by: Jack Hou <[email protected]>