Remove submit from async read pixels. User must submit.

Bug: chromium:1087118

Change-Id: Iab152ac483787fbdcca448aee0c4b9d2b354a92b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/292840
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
7 files changed