1. Open Youtube.com 2. Select the + (create) icon in the top right 3. Select upload video 4. Select Files and pick a video 5. Wait for animation to transition to Details page <rdar://problem/65863380>
Created attachment 404963 [details] screenshot
Committed r264775: <https://trac.webkit.org/changeset/264775>
webkit-patch land shouldn't have closed this.
I'd be awesome it could coud come up with a reduced test case. Otherwise I'll try to get it from the actual page.
From an early review it looks like the patch is not causing the regression but unveiling a pre-existing bug. I'll check it out.
BTW this is caused by 210089 not by the r262124. It's just the latter unveiled it.
Should be fixed now that the patch for bug 210089 landed