Enable vertex ID support on Metal
Enable vertex ID support on Metal

This allows the tessellated stroke renderer to run on Metal.

Change-Id: Ia6bd4008a3310cd316abdc2715efcec3916c6bfa
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/408358
Reviewed-by: Chris Dalton <ef7fc3a08ada7d31f16e9a18b5f3c728256e041e@google.com>
Commit-Queue: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>

google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia