Prioritize most-recently-enabled link-handling app

In the case when multiple apps handle a given web-link action,
all of which have been marked as "launch the app instead of a
browser" and so are otherwise ambiguous, always prefer the app
that was most recently placed into the always-handle-links state.

Bug 22051035

Change-Id: I3f43c19b0d7b74e9843445e41971bb5433affb1c