Issue 803924  has been merged into this issue.

https://chromium-review.googlesource.com/c/chromium/src/+/922445 takes care of this.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/97d10f2b699878b3f49229eaa2a0ca4dc1a722ae

commit 97d10f2b699878b3f49229eaa2a0ca4dc1a722ae
Author: Khushal <khushalsagar@chromium.org>
Date: Fri Feb 16 07:59:47 2018

gpu: Ensure RingBuffer maintains aligned memory offsets.

When requesting a buffer for OOP raster, the client requests the
largest free size for which no tokens are pending, and can be allocated
without waiting. This is queried from RingBuffer::GetLargestFreeSize.
However, since this size is rounded up to the next alignment when making
the allocation, this results in synchronously waiting on tokens to make
room for the extra padding.

Ensure that ShrinkLastBlock rounds up the new size for the block so
the buffer always has memory aligned free size.

R=enne@chromium.org, piman@chromium.org

Bug:  803925 
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Iff1286b6f412f126dbf33300387f85f9c21e91ed
Reviewed-on: https://chromium-review.googlesource.com/922445
Commit-Queue: Khushal <khushalsagar@chromium.org>
Reviewed-by: enne <enne@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537250}
[modify] https://crrev.com/97d10f2b699878b3f49229eaa2a0ca4dc1a722ae/gpu/command_buffer/client/ring_buffer.cc
[modify] https://crrev.com/97d10f2b699878b3f49229eaa2a0ca4dc1a722ae/gpu/command_buffer/client/ring_buffer.h
[modify] https://crrev.com/97d10f2b699878b3f49229eaa2a0ca4dc1a722ae/gpu/command_buffer/client/ring_buffer_test.cc
[modify] https://crrev.com/97d10f2b699878b3f49229eaa2a0ca4dc1a722ae/gpu/command_buffer/client/transfer_buffer_unittest.cc