we have create a branch called oilpan to perform experiments with putting DOM nodes in a garbage collected heap. The work is exploratory and experimental at this point and we are not planning on merging this branch back to the main tree. Therefore, feel free to ignore review emails with the [oilpan] prefix (unless you are interested in the experiments of course).
If our experiments look promising we will provide design docs as usual before landing anything in the main tree. For now we need to carry out some experiments to come up with a design that we believe will work.