e87e849e0f
Until now, directory locks were dropped when the last strong reference was removed or after calling Drop explicitly. The dependency on ref-counting makes it less obvious when directory locks are dropped for real and it's also difficult to release them asynchronously eventually. This patch removes the directory lock unregistration from the destructor, so from now on, directory locks must be always dropped explicitly. Differential Revision: https://phabricator.services.mozilla.com/D197294