This patch addresses both Bug 1551913 and Bug 1552206.
This patches the update directory permission-fixing code.
This also fixes a related bug that I discovered while testing this patch: nsAutoSid doesn't actually work because both PSID and HANDLE are both typedef'ed from void*, so the compiler can't actually tell the difference between them and ends up calling CloseHandle instead of FreeSid. To fix this, I removed nsAutoSid and replaced it with UniqueSidPtr, a UniquePtr type that uses a custom deleter class to free the SID properly.
Differential Revision: https://phabricator.services.mozilla.com/D34941
--HG--
rename : toolkit/mozapps/update/common/win_dirent.cpp => toolkit/mozapps/update/common/updateutils_win.cpp
rename : toolkit/mozapps/update/common/win_dirent.h => toolkit/mozapps/update/common/updateutils_win.h
extra : moz-landing-system : lando