[Windows/Ozone] Enable EGL on Windows platform w/ Ozone pt. 2

Follow-up to
https://chromium-review.googlesource.com/c/chromium/src/+/1048043.

Also removes OSMesa implementation on Windows platform.
Also removes CreateNativeViewGLSurfaceEGL.

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: Ie7bdcfc5fbe24a24df5eb6416bb6062812a7cc1f
Reviewed-on: https://chromium-review.googlesource.com/1055680
Commit-Queue: Mustafa Çamurcu <camurcu@google.com>
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: kylechar <kylechar@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559233}
6 files changed