As you can see on the buildbot, there are CSS parser leaks that occur when running layout tests. I have a fix for these under development.
My forthcoming patch requires the patch in bug 7345.
Created attachment 6593 [details] patch, including change log
Comment on attachment 6593 [details] patch, including change log Looks great. Went over it in person. One error found with - m_stylesheetDoc = 0; in void XSLStyleSheetImpl::clearDocuments() We'll also need to make sure we performance test before landing. r=me.