In Bug 1025709, an additional setting of mNeedsRefreshes = true as added to nsTransitionManager::WalkTransitionRule: http://hg.mozilla.org/mozilla-central/rev/31695984cfe2#l5.65 now at: http://hg.mozilla.org/mozilla-central/file/738469449872/layout/style/nsTransitionManager.cpp#l655 According to bug 1048838 comment 19 this may cause unnecessary work when we have multiple style flushes. We should see if there is a way to remove this. Also, while we're at it, as also mentioned in bug 1048838 comment 19, we should also investigate why WalkTransitionRule needs a null-check.

For what it's worth: * I've been running for at least a month (desktop and B2G phone) with the mNeedsRefreshes = true removed, and haven't noticed any problems. * there was a problem when I removed the null-check

I removed the removal from my tree because it was breaking all but the first transition in https://bug1110277.bugzilla.mozilla.org/attachment.cgi?id=8535092 , at least back when I was debugging that testcase.

This works for me, even for the test case in comment 2. Applies on top of the patch for bug 1117603.

Comment on attachment 8576461 [details] [diff] [review] Don't force transitions to refresh their style rule r=dbaron

I'm waiting for bug 1117603 to land before I land this.

Looks like this might trigger a test failure after all: browser/components/customizableui/test/browser_989751_subviewbutton_class.js | Uncaught exception - Condition timed out: () => !PanelUI.multiView.hasAttribute("transitioning")

From: https://treeherder.mozilla.org/#/jobs?repo=try&revision=d224f99253a5

After some changes in bug 1117603, looks like this might be ok now but I've retriggered the jobs that failed last time in case I just happened to get lucky: https://treeherder.mozilla.org/#/jobs?repo=try&revision=7c0d57b67523

Backed out because it blocked bug 1117603 from being backed out. https://hg.mozilla.org/integration/mozilla-inbound/rev/5329cda711c8

Can this reland now that bug 1117603 stuck?

(In reply to David Baron [:dbaron] ⏰UTC-7 from comment #11) > Can this reland now that bug 1117603 stuck? Yes! (I was just running it through try over the weekend and making sure bug 1117603 really stuck this time!) https://hg.mozilla.org/integration/mozilla-inbound/rev/7edc16a9d48f Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=72968ef6f7ef