Tiles on bottom of screen are not always allocated when necessary
Created attachment 233749 [details] Patch
<rdar://problem/16976937>
Comment on attachment 233749 [details] Patch Broke all the tests!
Comment on attachment 233749 [details] Patch No tests
Created attachment 233761 [details] Patch
http://trac.webkit.org/changeset/170414
Looks like the test added by this patch is failing on some bots: http://build.webkit.org/results/Apple%20Mavericks%20Release%20WK2%20(Tests)/r170415%20(6597)/compositing/visible-rect/iframe-no-layers-pretty-diff.html
http://build.webkit.org/results/Apple%20MountainLion%20Release%20WK2%20(Tests)/r170415%20(19320)/compositing/visible-rect/iframe-no-layers-pretty-diff.html
Re-opened since this is blocked by bug 134291
Sorry, I can't figure out what the right fix is because I don't know the context so I'm rolling out the patch for now.
This was rolled out in <http://trac.webkit.org/changeset/170417>
Created attachment 233862 [details] Patch
http://trac.webkit.org/changeset/170597