Enable required extensions for Chromium to use the Metal backend. This includes: EGL_ANGLE_display_texture_share_group EGL_ANGLE_display_semaphore_share_group EGL_ANGLE_robust_resource_initialization GL_EXT_debug_marker Bug: angleproject:4847 Bug: angleproject:4930 Bug: angleproject:4929 Bug: chromium:1112800 Bug: angleproject:4946 Change-Id: Ibacb6badf9f784dae3ca42514142ef13ee7297b8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2332863 Commit-Queue: Jonah Ryan-Davis <jonahr@google.com> Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>