Widen --harmony-for-in flag to throw errors in PreParser

Widen --harmony-for-in flag to throw errors in PreParser

The first version of --harmony-for-in avoided throwing PreParser
errors in order to retain use counting. This patch threads
use_counts_ through to the PreParser to allow use counting in
the PreParser while also throwing errors for this case.

Also slightly refactored the Parser code to do a little less
code duplication.

BUG=v8:4942
LOG=y

Committed: https://crrev.com/739947880cd1e9a8cc1ad1d6c26ca5a1442541f3
Cr-Commit-Position: refs/heads/master@{#35780}

[adamk, 2016-04-22 18:23:40]

adamk@chromium.org changed reviewers:
+ rossberg@chromium.org

[rossberg, 2016-04-25 11:42:53]

lgtm

[adamk, 2016-04-25 23:42:56]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2016-04-25 23:43:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1913203002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1913203002/1

[commit-bot: I haz the power, 2016-04-26 00:29:45]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-26 00:30:00]

Description was changed from

==========
Widen --harmony-for-in flag to throw errors in PreParser

The first version of --harmony-for-in avoided throwing PreParser
errors in order to retain use counting. This patch threads
use_counts_ through to the PreParser to allow use counting in
the PreParser while also throwing errors for this case.

Also slightly refactored the Parser code to do a little less
code duplication.

BUG=v8:4942
LOG=y
==========

to

==========
Widen --harmony-for-in flag to throw errors in PreParser

The first version of --harmony-for-in avoided throwing PreParser
errors in order to retain use counting. This patch threads
use_counts_ through to the PreParser to allow use counting in
the PreParser while also throwing errors for this case.

Also slightly refactored the Parser code to do a little less
code duplication.

BUG=v8:4942
LOG=y

Committed: https://crrev.com/739947880cd1e9a8cc1ad1d6c26ca5a1442541f3
Cr-Commit-Position: refs/heads/master@{#35780}
==========

[commit-bot: I haz the power, 2016-04-26 00:30:01]

Patchset 1 (id:??) landed as
https://crrev.com/739947880cd1e9a8cc1ad1d6c26ca5a1442541f3
Cr-Commit-Position: refs/heads/master@{#35780}