Currently we're relying on LineBuilder's destructor to handle updating
the last line, if required. In order to fix an issue with our absolute
positioning code, we need to be able to update the last line earlier
than that. Remove the destructor and replace it with an explicit call to
LineBuilder::update_last_line().
No functional changes.
Instead of reaching into the IFC of the LineBuilder from the BFC, we
should let LineBuilder determine how to deal with the running vertical
float clearance. No functional changes.
If a block with inline children ends with a line break clearing any
floats, we not only need to take the introduced clearance into account
for the next line box, but the containing block needs to set the correct
height as well.
Since the spec calls for using the last line box' bottom as the resolved
height (if treated as auto), we now correctly apply the clearance to the
previous line box' bottom coordinate.
Fixes#4058.
