Add ninja console pool support to GN

Add ninja console pool support to GN

Allow GN actions to specify "console = true", which will translate into
a "pool = console" setting in the generated ninja files. The console
pool allows a ninja target to have unbuffered io, access to standard
input, and is limited to one target at a time.

R=brettw@chromium.org
BUG=

Committed: https://crrev.com/b52c507ecb15e3eaf6051cba0de0cbaf69fe200a
Cr-Commit-Position: refs/heads/master@{#350321}

[tsniatowski, 2015-09-21 09:30:55]

Having something like this in GN would make some of the heavy-lifting actions we
have downstream a bit more friendly. PTAL.

[tsniatowski, 2015-09-21 09:35:06]

On 2015/09/21 09:30:55, tsniatowski wrote:
> Having something like this in GN would make some of the heavy-lifting actions
we
> have downstream a bit more friendly. PTAL.

An alternative approach that would somewhat complicate the code and need more
tests would be to have a generic pool [string] option on targets, it would have
to declare the pools then, handle duplicates, conflicts with builtin / link
pools and so on. I'm not sure if it'd be worth it.

[brettw, 2015-09-22 19:35:03]

Interesting.

Can you add "console" to the list of variables accepted by action and
action_foreach in functions_target.cc? (It's not quite up-to-date now, but we
shouldn't make it any less up-to-date.)

LGTM with that.

[tsniatowski, 2015-09-23 06:28:14]

On 2015/09/22 19:35:03, brettw wrote:
> Interesting.
> 
> Can you add "console" to the list of variables accepted by action and
> action_foreach in functions_target.cc? (It's not quite up-to-date now, but we
> shouldn't make it any less up-to-date.)
> 
> LGTM with that.

Done that, checked --help on action and action foreach. Thanks!

[tsniatowski, 2015-09-23 06:28:20]

The CQ bit was checked by tsniatowski@opera.com

[tsniatowski, 2015-09-23 06:28:20]

The patchset sent to the CQ was uploaded after l-g-t-m from brettw@chromium.org
Link to the patchset: https://codereview.chromium.org/1358803002/#ps40001
(title: "update action/action_foreach doc")

[commit-bot: I haz the power, 2015-09-23 06:28:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1358803002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1358803002/40001

[commit-bot: I haz the power, 2015-09-23 06:44:24]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-09-23 06:44:57]

Patchset 3 (id:??) landed as
https://crrev.com/b52c507ecb15e3eaf6051cba0de0cbaf69fe200a
Cr-Commit-Position: refs/heads/master@{#350321}