When the last line in the shape overlaps with the shape bottom boundaries we need to clear the computed segments. (We need to compute the segments anyway, since shape-outside's code uses the same code path to determine its segments and the line containing is not a requirement in that case.) Rather then doing the job in RenderBlock::LineBreaker::nextLineBreak I moved the functionality to its correct place to pushShapeContentOverflowBelowTheContentBox. Now all the overflow related functionality is located in one function.
Created attachment 205425 [details] proposed patch
Created attachment 206917 [details] updated patch after r152800
Comment on attachment 206917 [details] updated patch after r152800 r=me
Comment on attachment 206917 [details] updated patch after r152800 Clearing flags on attachment: 206917 Committed r152906: <http://trac.webkit.org/changeset/152906>
All reviewed patches have been landed. Closing bug.