Load the WGL_NV_DX_interop entry points in FunctionsWGL. BUG=540829 Change-Id: Iab080789f2a21b900e2641aa97c0e3392d007391 Reviewed-on: https://chromium-review.googlesource.com/316802 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>