Update ANGLE_platform_angle_d3d to use a device type enum instead of WARP bool. BUG=angle:490 Change-Id: I1555e7f09b23138753e52ddf720d088587f7cadb Reviewed-on: https://chromium-review.googlesource.com/232104 Reviewed-by: Shannon Woods <shannonwoods@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>