Update V8 to version 4.3.48.1 (cherry-pick).

Update V8 to version 4.3.48.1 (cherry-pick).

Summary of changes available at:
https://chromium.googlesource.com/v8/v8/+log/c18bc92e..eb476c80

Please follow these instructions for assigning/CC'ing issues:
https://code.google.com/p/v8-wiki/wiki/TriagingIssues

TBR=hablich@chromium.org,machenbach@chromium.org,yangguo@chromium.org,vogelheim@chromium.org
NOTRY=true

Committed: https://crrev.com/27f3e3354e9993b3ef3075470881f51644ff4ee5
Cr-Commit-Position: refs/heads/master@{#321475}

[v8-autoroll, 2015-03-19 22:18:47]

The CQ bit was checked by v8-autoroll@chromium.org

[commit-bot: I haz the power, 2015-03-19 22:19:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1019743003/1

[Michael Achenbach, 2015-03-19 22:29:57]

CC TPM. This roll-fix is probably more stable then the predecessor 4.3.48. I
hope it makes it into the branch instead of the 4.3.48.

[Michael Achenbach, 2015-03-20 00:09:45]

On 2015/03/19 22:29:57, Michael Achenbach (travelling) wrote:
> CC TPM. This roll-fix is probably more stable then the predecessor 4.3.48. I
> hope it makes it into the branch instead of the 4.3.48.

Only  mac_chromium_rel_ng missing. Setting notry from here, as this cherry-pick
includes an important revert on top of the last roll that passed CQ.

[Michael Achenbach, 2015-03-20 00:10:00]

The CQ bit was unchecked by machenbach@chromium.org

[Michael Achenbach, 2015-03-20 00:10:02]

The CQ bit was checked by machenbach@chromium.org

[commit-bot: I haz the power, 2015-03-20 00:10:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1019743003/1

[commit-bot: I haz the power, 2015-03-20 00:11:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-20 00:12:06]

Patchset 1 (id:??) landed as
https://crrev.com/27f3e3354e9993b3ef3075470881f51644ff4ee5
Cr-Commit-Position: refs/heads/master@{#321475}