Remove gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT.

GPU_READ_CPU_READ_WRITE_PERSISTENT is always handled the same way as
GPU_READ_CPU_READ_WRITE, so we no longer need it.

Change-Id: I5ab71dd9c80427f9d3a8c1d46050b66fd77138d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1570813
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652051}
18 files changed