The recomputeVirtualViewportFromViewportArguments method already contains the check, as pointed out by cgarcia on bug #113829 =)
Created attachment 196340 [details] Patch
Comment on attachment 196340 [details] Patch Perfect!
The commit-queue encountered the following flaky tests while processing attachment 196340 [details]: fast/js/dfg-inline-resolve.html bug 113046 (author: fpizlo@apple.com) The commit-queue is continuing to process your patch.
Comment on attachment 196340 [details] Patch Clearing flags on attachment: 196340 Committed r147552: <http://trac.webkit.org/changeset/147552>
All reviewed patches have been landed. Closing bug.