ozone: Fix flow control regression in ARM swap buffers code path

ozone: Fix flow control regression in ARM swap buffers code path

The early return after PostTaskAndReply() in
GLSurfaceOzoneSurfaceless::SwapBuffersAsync was erroneously removed in
f960a95 ("Split up synchronous & asynchronous swap buffers APIs").  This
adds it back.

It also removes the else after return; that's against the style guide.

BUG=560553
TEST=boot chrome on veyron_jerry

Committed: https://crrev.com/c63975ddfff98deaa93095cee0834ccf6b4c33ea
Cr-Commit-Position: refs/heads/master@{#361349}

[spang, 2015-11-24 15:28:09]

spang@chromium.org changed reviewers:
+ alexst@chromium.org

[alexst (slow to review), 2015-11-24 15:39:59]

lgtm

[spang, 2015-11-24 15:40:07]

The CQ bit was checked by spang@chromium.org

[commit-bot: I haz the power, 2015-11-24 15:41:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1475683002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1475683002/1

[commit-bot: I haz the power, 2015-11-24 16:08:19]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-24 16:09:00]

Patchset 1 (id:??) landed as
https://crrev.com/c63975ddfff98deaa93095cee0834ccf6b4c33ea
Cr-Commit-Position: refs/heads/master@{#361349}