After r138724, WebKit1.MemoryCachePruneWithinResourceLoadDelegate started to failing intermittently. The code changed in the said revision is never ran nor is ImageLoader ever created. Tools/Scripts/run-api-tests --debug WebKit1\.MemoryCacheDisableWithinResourceLoadDelegate WebKit1\.MemoryCachePruneWithinResourceLoadDelegate
<rdar://problem/12953534>
Temporarily disabled the test in http://trac.webkit.org/changeset/138753 for now.
This started failing slightly earlier, actually, sometime before r138718 at least: http://build.webkit.org/builders/Apple%20Lion%20Debug%20WK1%20%28Tests%29/builds/5642 That bot's last successful run was at r138707.
I'm able to reproduce this back to r138700, fwiw.