Suppress an uninitialized read in ThreadHeap<>::sweepNormalPages

Committed: https://crrev.com/f032b471042c2a93d504c5fdeb8a685dd06e8962
Cr-Commit-Position: refs/heads/master@{#291809}

[Jeffrey Yasskin, 2014-08-25 23:25:17]

The CQ bit was checked by jyasskin@chromium.org

[commit-bot: I haz the power, 2014-08-25 23:28:41]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jyasskin@chromium.org/502233002/20001

[commit-bot: I haz the power, 2014-08-26 00:07:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-08-26 00:07:59]

Failed to commit the patch.

[Jeffrey Yasskin, 2014-08-26 00:26:43]

The CQ bit was checked by jyasskin@chromium.org

[commit-bot: I haz the power, 2014-08-26 00:30:14]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jyasskin@chromium.org/502233002/20001

[Jeffrey Yasskin, 2014-08-26 00:31:32]

Committed patchset #2 to pending queue manually as 8da39ba (presubmit
successful).

[haraken, 2014-08-26 00:55:20]

LGTM

[Mads Ager (chromium), 2014-08-26 06:11:59]

LGTM

After the git migration it looks a little hard to figure out when the fix has
been picked up by the bots. The fix is in, so we should revert this change again
soon. The fix is https://src.chromium.org/viewvc/blink?revision=180854.

[Jeffrey Yasskin, 2014-08-26 21:12:00]

A revert of this CL (patchset #2) has been created in
https://codereview.chromium.org/507833002/ by jyasskin@chromium.org.

The reason for reverting is: The fix
(https://src.chromium.org/viewvc/blink?revision=180854) should be included by
the Blink roll in http://crrev.com/ecb9875276ccd..

[commit-bot: I haz the power, 2014-09-10 02:39:18]

Patchset 2 (id:??) landed as
https://crrev.com/f032b471042c2a93d504c5fdeb8a685dd06e8962
Cr-Commit-Position: refs/heads/master@{#291809}