Bug 112490 Patch to fix the mess I made
I have done bad things. I now prostrate myself and humbly ask that some gracious soul submit this patch (which I will attach forthwith) so that I may redeem myself. Basically, I (well really John but I made him do it) moved the ResourceMapping stuff to API but we missed a few things that needed to be done, causing great grief to the JDT team. Please spare the lashes as I have a low pain threshold.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/model/WorkingSetAdapterFactory.java
/*
     * Adapter for converting a working set to a resource mapping for
     * use by object contributions.
     */
    class ContributorResourceAdapter implements IContributorResourceAdapter2 {