Reland: Added SyncToken command buffer trait to help with IPC messages

Reland: Added SyncToken command buffer trait to help with IPC messages

Revert "Revert of Added SyncToken command buffer trait to help with IPC messages. (patchset #1 id:1 of https://codereview.chromium.org/1394543003/ )"

This reverts commit 77970f1c3cd71d535a248d6e15f14081312b300a.

This CL is relands the SyncToken command buffer trait changes but also
fixes the alignment issues found on android.

R=piman@chromium.org
BUG=514815
Committed: https://crrev.com/1e5cd82449106d3550e4c896d42cc8af01197a4a
Cr-Commit-Position: refs/heads/master@{#353555}

[piman, 2015-10-12 16:32:16]

https://codereview.chromium.org/1399173002/diff/1/gpu/ipc/gpu_command_buffer_...
File gpu/ipc/gpu_command_buffer_traits.cc (right):

https://codereview.chromium.org/1399173002/diff/1/gpu/ipc/gpu_command_buffer_...
gpu/ipc/gpu_command_buffer_traits.cc:60: m->WriteBytes(&p, sizeof(p));
I'd suggest writing and reading each field individually, that avoids writing and
reading uninitialized data (padding bytes).

[David Yen, 2015-10-12 16:57:44]

https://codereview.chromium.org/1399173002/diff/1/gpu/ipc/gpu_command_buffer_...
File gpu/ipc/gpu_command_buffer_traits.cc (right):

https://codereview.chromium.org/1399173002/diff/1/gpu/ipc/gpu_command_buffer_...
gpu/ipc/gpu_command_buffer_traits.cc:60: m->WriteBytes(&p, sizeof(p));
On 2015/10/12 16:32:15, piman (slow to review) wrote:
> I'd suggest writing and reading each field individually, that avoids writing
and
> reading uninitialized data (padding bytes).

Done.

[piman, 2015-10-12 17:34:06]

lgtm

[David Yen, 2015-10-12 17:36:47]

The CQ bit was checked by dyen@chromium.org

[commit-bot: I haz the power, 2015-10-12 17:40:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1399173002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1399173002/20001

[commit-bot: I haz the power, 2015-10-12 18:07:25]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-12 18:08:46]

Patchset 2 (id:??) landed as
https://crrev.com/1e5cd82449106d3550e4c896d42cc8af01197a4a
Cr-Commit-Position: refs/heads/master@{#353555}