At that occasion, replace five existing formatting functions for one-unit time strings by a single consistent interface with the aim to make time formatting functions easier to use by highlighting the availability of different formatting options.

Also at that occasion, rename IDS_TIME_DURATION_LONG* to IDS_TIME_LONG* to be more consistent with other IDS_TIME* ids.

BUG=339835
TEST=full unit test coverage
TBR=oshima@chromium.org (for resolution_notification_controller.cc)
TBR=jennyz@chromium.org (for ash/system)
TBR=asanka@chromium.org (for download_item_model.cc)
TBR=tim@chromium.org (for profile_sync_service.cc)
TBR=xiyuan@chromium.org (for imageburner_ui.cc)
TBR=estade@chromium.org (for foreign_session_handler.cc, policy_ui.cc)

Review URL: https://codereview.chromium.org/147443007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253830 0039d316-1c4b-4281-b951-d872f2087c98