Ting-Yu Lin
b4c09dcd55
`nsColumnSetFrame` may reflow the last column with an unconstrained block-size, e.g. at the end of the last column balancing reflow [1]. When that happens, i.e., `reflowLastColumnWithUnconstrainedAvailBSize=true`, we want to force reflow all the floats to make sure they are fragmented correctly, by setting `mMustReflowPlaceholders=true` to ensure the line containing floats is dirty [2]. This edit alone (in nsColumnSetFrame.cpp) fixes `column-balancing-with-floats-001.html`. However, to fix all the assertions seen in bug 2054166 comment 1, we need to generalize the fix in Bug 1441048 Part 2 https://hg-edge.mozilla.org/mozilla-central/rev/30e4adcd2dbd This patch extends `ReflowInput::IsInFragmentedContext()` to catch more scenarios and use the helper when marking lines dirty so that the above `mMustReflowPlaceholders` trick works. Without this patch, `column-balancing-with-floats-002.html` can trigger soft assertions in nsColumnSetFrame [3] and nsFlexContainerFrame [4]. [1] https://searchfox.org/firefox-main/rev/aaf0207c409c5f6479cc92bc1bf407a453d63cdc/layout/generic/nsColumnSetFrame.cpp#1176-1188 [2] https://searchfox.org/firefox-main/rev/aaf0207c409c5f6479cc92bc1bf407a453d63cdc/layout/generic/nsBlockFrame.cpp#3417-3420 [3] https://searchfox.org/firefox-main/rev/7d5b291d2351f7d04c504b03fa22ec3dcdf81b54/layout/generic/nsColumnSetFrame.cpp#1313-1316 [4] https://searchfox.org/firefox-main/rev/7d5b291d2351f7d04c504b03fa22ec3dcdf81b54/layout/generic/nsFlexContainerFrame.cpp#6008-6011 Differential Revision: https://phabricator.services.mozilla.com/D312101