Always validate GrBackendTextures passed to YUV image factories

Change-Id: I73a301fcdf13fceb82c94b0c68ac9386aa38e16d
Reviewed-on: https://skia-review.googlesource.com/115126
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed