Bug 919813 part 1: Remove never-checked return value from frame methods SetPrevInFlow, SetNextInFlow, SetPrevContinuation, SetNextContinuation. r=mats
Bug 919813 part 2: Upgrade NS_ERROR to MOZ_ASSERT in nsFrame's impl of SetPrevInFlow, SetNextInFlow, SetPrevContinuation, SetNextContinuation. rs=mats