This was introduced by the fix for bug 132298 . The code removal in RenderMultiColumnSet::endFlow(). So the code there was necessary after all (it's just that we didn't have any tests for it), but it's messy, so better find a cleaner way of doing this. How about inserting a column break at the placeholder and have a strut do the job for us?
Created attachment 231766 [details] Patch
@hyatt - can you review, please? This will require some test rebaselining, because the flow thread will become taller than before in some cases (without affecting the set heights). I'm not exactly sure why code had to be removed from endFlow() as part of fixing bug 132298, but it was admittedly kind of ugly. I hope this new attempt won't mess up anything for compositing.
Comment on attachment 231766 [details] Patch Attachment 231766 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/6526303687671808 New failing tests: fast/multicol/span/span-as-immediate-child-generated-content.html fast/multicol/span/span-as-immediate-child-complex-splitting.html fast/multicol/span/span-as-immediate-columns-child-dynamic.html fast/multicol/span/span-as-immediate-columns-child.html fast/multicol/span/span-as-nested-columns-child-dynamic.html fast/multicol/span/span-as-nested-columns-child.html
Created attachment 231770 [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 10.8.5
So, yeah, that were the "failures" I kind of expected. Need to rebaseline this. I don't know about the image failures, and how I could have caused them, though. Looks like everything is off by ~half a pixel, horizontally. Compositing issue? I only expected render tree dump differences.
Comment on attachment 231766 [details] Patch Attachment 231766 [details] did not pass mac-ews (mac): Output: http://webkit-queues.appspot.com/results/5116720486285312 New failing tests: fast/multicol/span/span-as-immediate-child-generated-content.html fast/multicol/span/span-as-immediate-child-complex-splitting.html fast/multicol/span/span-as-immediate-columns-child-dynamic.html fast/multicol/span/span-as-immediate-columns-child.html fast/multicol/span/span-as-nested-columns-child-dynamic.html fast/multicol/span/span-as-nested-columns-child.html
Created attachment 231772 [details] Archive of layout-test-results from webkit-ews-02 for mac-mountainlion The attached test failures were seen while running run-webkit-tests on the mac-ews. Bot: webkit-ews-02 Port: mac-mountainlion Platform: Mac OS X 10.8.5
Comment on attachment 231766 [details] Patch Attachment 231766 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/5623377108664320 New failing tests: fast/multicol/span/span-as-immediate-child-generated-content.html fast/multicol/span/span-as-immediate-child-complex-splitting.html fast/multicol/span/span-as-immediate-columns-child-dynamic.html fast/multicol/span/span-as-immediate-columns-child.html fast/multicol/span/span-as-nested-columns-child-dynamic.html fast/regions/cssom/region-range-for-box-crash.html fast/multicol/span/span-as-nested-columns-child.html
Created attachment 231778 [details] Archive of layout-test-results from webkit-ews-16 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-16 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.5
Comment on attachment 231766 [details] Patch Attachment 231766 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/6674724436312064 New failing tests: fast/multicol/span/span-as-immediate-child-generated-content.html fast/multicol/span/span-as-immediate-child-complex-splitting.html fast/multicol/span/span-as-immediate-columns-child-dynamic.html fast/multicol/span/span-as-immediate-columns-child.html fast/multicol/span/span-as-nested-columns-child-dynamic.html fast/multicol/span/span-as-nested-columns-child.html
Created attachment 231782 [details] Archive of layout-test-results from webkit-ews-12 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-12 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.5
Comment on attachment 231766 [details] Patch Hi, Apologies that your patch was not reviewed in a timely manner. Since it's now quite old, I am removing it from the review request queue. Please consider rebasing it on trunk and resubmitting. To increase the chances of getting a review, consider using 'Tools/Scripts/webkit-patch upload --suggest-reviewers' to CC reviewers who might be interested in this bug.
This is no longer applicable given Regions (which the new multicol was based on) was removed in bug 174978.