Consider external format when determining whether YCBCR information is valid

Bug: b/292023877
Change-Id: I4be08117a2b697fb647feac492af2a3fc01a66dc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/740276
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Nicolette Prevost <nicolettep@google.com>
1 file changed