Bridge Method Injector Opportunities

Where might we use the Bridge Method Injector in Guava?

We're not yet sure whether we want to use it at all, but part of making that decision will be having a list of possible uses in front of us.

Note that any of these changes might introduce source incompatibilities (e.g., for people who call ImmutableSet.of(immediateFuture(...))).

• Iterables.(various) -> FluentIterable
• ImmutableMultiset.elementSet -> ImmutableSet
• Iterators.forArray, singletonIterator -> UnmodifiableListIterator
• Splitter.split -> List (or FluentIterable if we could depend on collect from base)
• Sets.filter (etc.) -> SetView
• Futures.immediate*Future -> ListenableScheduledFuture?