[PATCH] Make getUnitForOffset a DWARFUnit method instead of a DWARFContext method.

[Frederic Riss]

Yeah, I did the minimal patch. Having it inherit from SmallVector allows to keep most of the other code (mostly in the Context) untouched. You'd have to implement a bunch of proxy methods to make the Context happy while not inheriting from the Vector, but it's doable as a later step if it's the road we want to go.

http://reviews.llvm.org/D5310