Split the swap chain into an abstract interface and a D3D9 implementation. TRAC #21926 Signed-off-by: Daniel Koch Signed-off-by: Geoff Lang Author: Nicolas Capens git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1445 736b8ea6-26fd-11df-bfd4-992fa37f6226