Enable SpriteVisuals to work along side HWNDs so that Angle rendered content can be hosted with Windows::UI::Composition APIs or XamlIslands in desktop Win32 applications. Includes a whitebox test, verified Win7 compatibility For more info see: https://docs.google.com/document/d/1ggv6H-aK1a3pXNMTtMF6h0Bv0rulIeBpBxBBCJYR6Zs/edit?usp=sharing Bug: angleproject:2947 Change-Id: Id005739553be2a6268cd4543f1b07aaf89760422 Reviewed-on: https://chromium-review.googlesource.com/c/1236844 Commit-Queue: James Clarke <james.clarke@microsoft.com> Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>
