Rename SwapChain to SwapChainD3D and move it to the D3D folder. BUG=angle:681 Change-Id: Idcf24556e590e07cc0b6cf640d4701353a0cda5e Reviewed-on: https://chromium-review.googlesource.com/238472 Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>