WebKit doesn't support the column-fill property. Instead it behaves as if 'column-fill' is set to 'auto'. This makes balancing impossible if height is specified.
Created attachment 204806 [details] Test case
Created attachment 204807 [details] Patch
Note that the patch is only for the (new) region based columns implementation.
Comment on attachment 204807 [details] Patch Attachment 204807 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/876137 New failing tests: fast/repaint/table-cell-collapsed-border-scroll.html fast/multicol/newmulticol/fixed-height-fill-balance.html
Created attachment 204825 [details] Archive of layout-test-results from webkit-ews-01 for mac-mountainlion The attached test failures were seen while running run-webkit-tests on the mac-ews. Bot: webkit-ews-01 Port: mac-mountainlion Platform: Mac OS X 10.8.3
Created attachment 204841 [details] Patch
New patch, attempted to fix fast/multicol/newmulticol/fixed-height-fill-balance.html on Mac (rounding error?) No idea why fast/repaint/table-cell-collapsed-border-scroll.html failed.
Comment on attachment 204841 [details] Patch Attachment 204841 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/895233 New failing tests: fast/repaint/table-cell-collapsed-border-scroll.html fast/multicol/newmulticol/fixed-height-fill-balance.html
Created attachment 204870 [details] Archive of layout-test-results from webkit-ews-08 for mac-mountainlion The attached test failures were seen while running run-webkit-tests on the mac-ews. Bot: webkit-ews-08 Port: mac-mountainlion Platform: Mac OS X 10.8.3
Comment on attachment 204841 [details] Patch Attachment 204841 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/858531 New failing tests: fast/repaint/table-cell-collapsed-border-scroll.html fast/multicol/newmulticol/fixed-height-fill-balance.html
Created attachment 204874 [details] Archive of layout-test-results from webkit-ews-04 for mac-mountainlion The attached test failures were seen while running run-webkit-tests on the mac-ews. Bot: webkit-ews-04 Port: mac-mountainlion Platform: Mac OS X 10.8.3
Comment on attachment 204841 [details] Patch Attachment 204841 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/865322 New failing tests: fast/multicol/newmulticol/fixed-height-fill-balance.html
Created attachment 204890 [details] Archive of layout-test-results from webkit-ews-15 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-15 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.3
Created attachment 204980 [details] Patch
Another attempt to make the test pass.
Comment on attachment 204980 [details] Patch Just to make sure, the behavior of the WebKit pagination API (which is built using columns) needs to be that you fill by default rather than balance. Does multicolumn applied to the RenderView properly set fill? Look at the method in RenderStyle that sets column styles based off the pagination mode, since I think in that case you want to also always set fill to auto to avoid balancing.
This patch only adds support for column-fill for the region based multicol implementation, and RenderMultiColumnBlock currently only supports real multicol. It doesn't support paged overflow. Even if it did (it should, at some point), it wouldn't be a problem, because paged overflow means that you get a used column-count of 1, so no balancing could possibly take place. BTW, RenderView doesn't inherit from RenderMultiColumnBlock. That would have been weird, anyway. Not sure what to do to get proper region based multicol support on a paginated RenderView (I assume this is desirable at some point). Probably need to get rid of RenderMultiColumnBlock and merge it into RenderBlock. In any case, would overriding computed style for column-fill be very healthy? Wouldn't it be better to let the renderer figure out how to treat it?
Comment on attachment 204980 [details] Patch r=me
Created attachment 212690 [details] Patch
The previous patch failed to land for some reason (looks like a bot problem). I've rebased master and uploaded a new patch. Please take a look.
@dhyatt: please see previous comment.
Created attachment 214244 [details] Patch
Can someone review+ and cq+ this one for me (I just rebased master again)?
Created attachment 214282 [details] Patch
Comment on attachment 214282 [details] Patch Clearing flags on attachment: 214282 Committed r157458: <http://trac.webkit.org/changeset/157458>
All reviewed patches have been landed. Closing bug.