Enhancement to the EGL_ANGLE_d3d_texture_client_buffer extension to
allow use of a shared D3D texture that can be multi-sampled.

BUG=angleproject:1917

Change-Id: Iaf59bbd575a5dfb29345f55b549bc4017bf2d7d0
Reviewed-on: https://chromium-review.googlesource.com/446907Reviewed-by: Bryan Bernhart <bryan.bernhart@intel.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>