nsCSSFrameConstructor::ConstructNonScrollableBlock() has logic to
determine whether to create a block formatting context for a block
frame. I refactor the function to make it reusable by
nsCSSFrameConstructor::ConstructDetailsFrame().
Also, make NS_NewBlockFrame() accept two arguments as other frame
factory functions so that it could be pointed by BlockFrameCreationFunc.
NS_NewBlockFormattingContext is changed accordingly.
The construction for a scrollable DetailsFrame will be further revised
in Part 3.
MozReview-Commit-ID: 8TwG9YMyGva
--HG--
extra : rebase_source : fffdd974df81a809a607491d2534aa8dd2d13ab1
