Disable experimental natives when creating a start-up snapshot.

Disable experimental natives when creating a start-up snapshot.

Re-installing experimental natives after deserialization causes failures if
said experimental native is already included in the snapshot. However, there
is no way to tell whether a certain harmony feature has been included.

Experimental natives may also be turned on/off on-demand, which a snapshot
that includes them would not support for all cases.

The simple solution for the meantime is to never include experimental natives
in the snapshot and initialize them after deserialization on-demand.

R=vogelheim@chromium.org

Committed: https://crrev.com/efe828e6999fe84a14a8a4bd0c5ddc9bac9d4dc0
Cr-Commit-Position: refs/heads/master@{#26982}

[Yang, 2015-03-04 07:45:15]

This is actually long overdue.

[vogelheim, 2015-03-04 12:40:32]

lgtm

[Yang, 2015-03-04 12:44:15]

The CQ bit was checked by yangguo@chromium.org

[commit-bot: I haz the power, 2015-03-04 12:44:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/981473002/1

[commit-bot: I haz the power, 2015-03-04 13:01:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-04 13:01:39]

Patchset 1 (id:??) landed as
https://crrev.com/efe828e6999fe84a14a8a4bd0c5ddc9bac9d4dc0
Cr-Commit-Position: refs/heads/master@{#26982}