A new extension EGL_ANGLE_d3d_typeless_texture_client_buffer is added
that allows creating EGL pbuffers from typeless D3D textures.

The extension increases the flexibility of the API compared to plain
EGL_ANGLE_D3D_texture_client_buffer. The colorspace for the created
EGL pbuffer can be set by using the EGL_GL_COLORSPACE attribute.
Internally this sets the ANGLE format of the buffer. There are new
ANGLE formats that are used specifically for typeless textures,
separate ones for SRGB and linear views into the D3D textures.

The extension is only supported on the D3D11 backend of ANGLE.

BUG=angleproject:2300
TEST=angle_white_box_tests

Change-Id: I6a6cb873d2cc0dca0b7f18a0f2cd35e7bafcb7d8
Reviewed-on: https://chromium-review.googlesource.com/873917Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>