Revert of [ast] Simplify FetchFreeVariables.

Revert of [ast] Simplify FetchFreeVariables. (patchset #1 id:1 of https://codereview.chromium.org/2491373004/ )

Reason for revert:
It's probably needed after all but we're lacking tests.

Original issue's description:
> [ast] Simplify FetchFreeVariables.
>
> This CL removes the ParseInfo argument from FetchFreeVariables, since it seems
> to have become unnecessary.
>
> R=verwaest@chromium.org
> BUG=

TBR=verwaest@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=

Committed: https://crrev.com/8538143c61664a6859e5f24374936b9e9edc92ce
Cr-Commit-Position: refs/heads/master@{#40964}

[neis, 2016-11-14 12:55:37]

The CQ bit was checked by neis@chromium.org

[neis, 2016-11-14 12:55:37]

Created Revert of [ast] Simplify FetchFreeVariables.

[commit-bot: I haz the power, 2016-11-14 12:55:47]

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, 2016-11-14 13:22:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-17 22:32:32]

Description was changed from

==========
Revert of [ast] Simplify FetchFreeVariables. (patchset #1 id:1 of
https://codereview.chromium.org/2491373004/ )

Reason for revert:
It's probably needed after all but we're lacking tests.

Original issue's description:
> [ast] Simplify FetchFreeVariables.
> 
> This CL removes the ParseInfo argument from FetchFreeVariables, since it seems
> to have become unnecessary.
> 
> R=verwaest@chromium.org
> BUG=

TBR=verwaest@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=
==========

to

==========
Revert of [ast] Simplify FetchFreeVariables. (patchset #1 id:1 of
https://codereview.chromium.org/2491373004/ )

Reason for revert:
It's probably needed after all but we're lacking tests.

Original issue's description:
> [ast] Simplify FetchFreeVariables.
>
> This CL removes the ParseInfo argument from FetchFreeVariables, since it seems
> to have become unnecessary.
>
> R=verwaest@chromium.org
> BUG=

TBR=verwaest@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=

Committed: https://crrev.com/8538143c61664a6859e5f24374936b9e9edc92ce
Cr-Commit-Position: refs/heads/master@{#40964}
==========

[commit-bot: I haz the power, 2016-11-17 22:32:33]

Patchset 1 (id:??) landed as
https://crrev.com/8538143c61664a6859e5f24374936b9e9edc92ce
Cr-Commit-Position: refs/heads/master@{#40964}