[API] Check for NULL external data pointer in ArrayBuffer::New()

[API] Check for NULL external data pointer in ArrayBuffer::New()

Embedders must not provide invalid pointers for external backing stores.

BUG=chromium:522128
LOG=n
R=cbruni@chromium.org

Committed: https://crrev.com/7fc7957be57d1cdfb0b7e1d76bdee78f4699774f
Cr-Commit-Position: refs/heads/master@{#30243}

[Jakob Kummerow, 2015-08-18 16:47:22]

Please take a look, and CQ it if you like it.

[Camillo Bruni, 2015-08-19 05:40:14]

The CQ bit was checked by cbruni@chromium.org

[Camillo Bruni, 2015-08-19 05:40:15]

lgtm

[commit-bot: I haz the power, 2015-08-19 05:40:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1289373004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1289373004/1

[commit-bot: I haz the power, 2015-08-19 06:30:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-19 06:31:09]

Patchset 1 (id:??) landed as
https://crrev.com/7fc7957be57d1cdfb0b7e1d76bdee78f4699774f
Cr-Commit-Position: refs/heads/master@{#30243}