Fix cluster-fuzz bug introduced in refs/heads/master@{#28796}.

Fix cluster-fuzz bug introduced in refs/heads/master@{#28796}.

Don't DCHECK when neutering that the buffer is not a SharedArrayBuffer;
instead, just return early.

BUG=chromium:498142, chromium:497295
R=jarin@chromium.org
LOG=n

Committed: https://crrev.com/4d6c309777ac11a22267605c3d7e159072750feb
Cr-Commit-Position: refs/heads/master@{#28892}

[Jarin, 2015-06-10 04:16:35]

You could use RUNTIME_ASSERT instead of DCHECK. That way it will be ignored by
clusterfuzz as it only throws, but it will still fail. This is what we do in
other runtime functions.

Could you please add the regression test to the test/mjsunit/regress directory?
(Name it regress-498142.js.)

[binji, 2015-06-10 05:21:06]

On 2015/06/10 at 04:16:35, jarin wrote:
> You could use RUNTIME_ASSERT instead of DCHECK. That way it will be ignored by
clusterfuzz as it only throws, but it will still fail. This is what we do in
other runtime functions.
> 
> Could you please add the regression test to the test/mjsunit/regress
directory? (Name it regress-498142.js.)

Done.

[Jarin, 2015-06-10 05:27:03]

lgtm. (Even though some test minimization + formatting + sane variable naming
would be nice.)

[binji, 2015-06-10 06:14:03]

On 2015/06/10 at 05:27:03, jarin wrote:
> lgtm. (Even though some test minimization + formatting + sane variable naming
would be nice.)

Done.

[binji, 2015-06-10 06:14:08]

The CQ bit was checked by binji@chromium.org

[binji, 2015-06-10 06:14:09]

The patchset sent to the CQ was uploaded after l-g-t-m from jarin@chromium.org
Link to the patchset: https://codereview.chromium.org/1174753002/#ps40001
(title: "nicer test")

[commit-bot: I haz the power, 2015-06-10 06:14:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1174753002/40001

[commit-bot: I haz the power, 2015-06-10 07:33:47]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-06-10 07:34:04]

Patchset 3 (id:??) landed as
https://crrev.com/4d6c309777ac11a22267605c3d7e159072750feb
Cr-Commit-Position: refs/heads/master@{#28892}