http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=css3%2Fflexbox%2Fanonymous-block-merge-crash.html%2Ccss3%2Fflexbox%2Fanonymous-block.html%2Ccss3%2Fflexbox%2Fauto-height-dynamic.html%2Ccss3%2Fflexbox%2Fchild-overflow.html%2Ccss3%2Fflexbox%2Fcolumns-auto-size.html%2Ccss3%2Fflexbox%2Fcross-axis-scrollbar.html%2Ccss3%2Fflexbox%2Fflex-algorithm-min-max.html%2Ccss3%2Fflexbox%2Fflex-algorithm-with-margins.html%2Ccss3%2Fflexbox%2Fflex-algorithm.html%2Ccss3%2Fflexbox%2Fflex-align-baseline.html%2Ccss3%2Fflexbox%2Fflex-align-column.html%2Ccss3%2Fflexbox%2Fflex-align-end.html%2Ccss3%2Fflexbox%2Fflex-align-max.html%2Ccss3%2Fflexbox%2Fflex-align-percent-height.html%2Ccss3%2Fflexbox%2Fflex-align-stretch.html%2Ccss3%2Fflexbox%2Fflex-align-vertical-writing-mode.html%2Ccss3%2Fflexbox%2Fflex-align.html%2Ccss3%2Fflexbox%2Fflex-flow-border.html%2Ccss3%2Fflexbox%2Fflex-flow-margins-auto-size.html%2Ccss3%2Fflexbox%2Fflex-flow-margins.html
Created attachment 133188 [details] Patch
mitz reverted in https://bugs.webkit.org/show_bug.cgi?id=81870. Turns out that the assert is just wrong, so I'm going to remove it. It's possible for there to be no lines if a flexbox has no children.
*** This bug has been marked as a duplicate of bug 81870 ***