The Wayland GPU offloading builds upon the work already laid by DRM render-nodes, DRI2/DRI3, and DMA-BUF and is implemented within a Wayland world. Right now GPU offloading can work with Wayland but there's no screen synchronization and thus tearing can happen, but that will ultimately be corrected.
Also desired as improvements is no server-side support for DRI PRIME, making no configuration support necessary, support for all graphics devices, hot-plugging support, and client-side buffer compatibility. Axel Davy has been the developer working on this GPU offloading support within Wayland. The design is using DRM-render nodes, DRI_PRIME with Mesa, and supports shutting down the dedicated GPU when it isn't rendering.
Axel has been working on Present support for XWayland, DRI3 XWayland support, the Mesa DRI PRIME patches for Wayland, and other changes. This developer gave a talk last weekend at FOSDEM 2014 about Wayland GPU offloading. If you're interested in learning many more details about the design, the current work, and the work ahead, check out Axel Davy's PDF slides.