[wasm] Require wasm explicit asm instantiation to be of a function.

[wasm] Require wasm explicit asm instantiation to be of a function.

We were not checking that the string passed to instantiateFromAsm
contains a function declaration (any declaration was allowed).

Fixes crash.

BUG=620649
BUG=v8:4203
R=aseemgarg@chromium.org

Committed: https://crrev.com/58920e04bce8435be4c98e36b3c10592ef1b206d
Cr-Commit-Position: refs/heads/master@{#37349}

[aseemgarg, 2016-06-28 18:45:42]

lgtm

[bradn, 2016-06-28 20:55:22]

The CQ bit was checked by bradnelson@google.com

[commit-bot: I haz the power, 2016-06-28 20:55:27]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-06-28 20:57:36]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-28 20:58:35]

Description was changed from

==========
[wasm] Require wasm explicit asm instantiation to be of a function.

We were not checking that the string passed to instantiateFromAsm
contains a function declaration (any declaration was allowed).

Fixes crash.

BUG=620649
BUG=v8:4203
R=aseemgarg@chromium.org
==========

to

==========
[wasm] Require wasm explicit asm instantiation to be of a function.

We were not checking that the string passed to instantiateFromAsm
contains a function declaration (any declaration was allowed).

Fixes crash.

BUG=620649
BUG=v8:4203
R=aseemgarg@chromium.org

Committed: https://crrev.com/58920e04bce8435be4c98e36b3c10592ef1b206d
Cr-Commit-Position: refs/heads/master@{#37349}
==========

[commit-bot: I haz the power, 2016-06-28 20:58:36]

Patchset 1 (id:??) landed as
https://crrev.com/58920e04bce8435be4c98e36b3c10592ef1b206d
Cr-Commit-Position: refs/heads/master@{#37349}