Looks like this is a left-over from several refactorings that changed the function. The remainder of detachCustomScrollbars definitely does not care about having a Frame. Patch forthcoming.
Created attachment 114412 [details] Trivial change: remove the check.
Comment on attachment 114412 [details] Trivial change: remove the check. Can you remove this because m_frame is never going to be null, or because m_frame is never dereferenced? If it is because m_frame is never going to be null, you can assert that.
(In reply to comment #2) > (From update of attachment 114412 [details]) > Can you remove this because m_frame is never going to be null, or because m_frame is never dereferenced? If it is because m_frame is never going to be null, you can assert that. The latter I am afraid: AFAICT this check was introduced because we would crash if we did not check the Frame but the code has changed and this check is not needed anymore.
Comment on attachment 114412 [details] Trivial change: remove the check. Clearing flags on attachment: 114412 Committed r100014: <http://trac.webkit.org/changeset/100014>
All reviewed patches have been landed. Closing bug.