** test resizes and incremental changes under reflow logging to make sure things are as expected
** test potential performance improvements
*** combine AddInlinePrefWidth and AddInlineMinWidth into one function to avoid two passes of text measurement(this could hurt the non-table cases, though, which often call GetPrefWith but not GetMinWidth)
*** make MarkIntrinsicWidthsDirty take a child that was dirty to allow blocks to optimize per-line