Migrated locale_mac.[h|mm| away from WTF::RetainPtr

Note that this required renaming locale_mac_test.cc into
locale_mac_test.mm, as scoped_nsobject.h would now be
indirectly included from there via locale_mac.h.

Bug: 929973
Change-Id: I70b6bcd1621b49ede8e2f09667d6f1f901567f48
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1495454
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#639948}
5 files changed