These are ALWAYS_INLINE functions that will forward the call to the Heap versions. Adding these allows us to make all the client code more terse, and also makes it easier to redirect the underlying writeBarrier implementation later for global GC work. Additionally, this will help make the global GC patch less of a mega patch and easier to review later. Also remove unused Heap::writeBarrierWithoutFence().
<rdar://problem/85318693>
Created attachment 444011 [details] proposed patch.
Thanks for the review. Landed in r285687: <http://trac.webkit.org/r285687>.