Add JSTypedArray's length in post-mortem metadata.

Add JSTypedArray's length in post-mortem metadata.

BUG=
[email protected]

Committed: https://crrev.com/c281c15d6dab8370a7805f0717502d260e0ad433
Cr-Commit-Position: refs/heads/master@{#30873}

[julien.gilli, 2015-09-23 05:06:03]

[email protected] changed reviewers:
+ [email protected], [email protected]

[Benedikt Meurer, 2015-09-23 05:13:09]

The CQ bit was checked by [email protected]

[Benedikt Meurer, 2015-09-23 05:13:10]

lgtm

[commit-bot: I haz the power, 2015-09-23 05:13:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1363683002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1363683002/1

[commit-bot: I haz the power, 2015-09-23 05:37:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-23 05:38:00]

Patchset 1 (id:??) landed as
https://crrev.com/c281c15d6dab8370a7805f0717502d260e0ad433
Cr-Commit-Position: refs/heads/master@{#30873}