Mark threaded CSSOM smooth scroll tests as slow

Mark threaded CSSOM smooth scroll tests as slow

Several tests in virtual/threaded/fast/scroll-behavior are flakily
timing out or coming very close to the time limit. Since most tests
are affected on at least one platform, this marks the entire test
suite as slow.

BUG=243871
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188746

[ajuma, 2015-01-20 21:24:47]

ajuma@chromium.org changed reviewers:
+ vollick@chromium.org

[ajuma, 2015-01-20 21:29:38]

Each of these layout tests actually runs several scroll animations, so an
alternative would be to split up each test into multiple tests, but that seems
pretty unwieldy.

[Ian Vollick, 2015-01-21 04:33:35]

On 2015/01/20 21:29:38, ajuma wrote:
> Each of these layout tests actually runs several scroll animations, so an
> alternative would be to split up each test into multiple tests, but that seems
> pretty unwieldy.

Seems reasonable. lgtm.

[ajuma, 2015-01-21 14:02:41]

The CQ bit was checked by ajuma@chromium.org

[commit-bot: I haz the power, 2015-01-21 14:03:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/838373003/1

[commit-bot: I haz the power, 2015-01-21 14:50:14]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=188746