Fix audio related GN args handling for Chrome OS

Fix audio related GN args handling for Chrome OS

use_pulseaudio should be false when use_cras is true.

"gn help declare_args" says:
  - Any code inside of the declare_args block will see the default
    values of previous variables defined in the block rather than
    the user-overridden value.

BUG=433082, 561142
Committed: https://crrev.com/55cb6ac985369376c823de679a19a93b4b28e275
Cr-Commit-Position: refs/heads/master@{#374306}

[hashimoto, 2016-02-08 09:36:01]

hashimoto@chromium.org changed reviewers:
+ dalecurtis@chromium.org

[DaleCurtis, 2016-02-08 19:12:42]

Ah, defines { defines { defines { defines } } } returns in another form :) lgtm

[hashimoto, 2016-02-09 02:33:36]

The CQ bit was checked by hashimoto@chromium.org

[commit-bot: I haz the power, 2016-02-09 02:38:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1678033002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1678033002/1

[commit-bot: I haz the power, 2016-02-09 04:37:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-02-09 04:38:33]

Description was changed from

==========
Fix audio related GN args handling for Chrome OS

use_pulseaudio should be false when use_cras is true.

"gn help declare_args" says:
  - Any code inside of the declare_args block will see the default
    values of previous variables defined in the block rather than
    the user-overridden value.

BUG=433082,561142
==========

to

==========
Fix audio related GN args handling for Chrome OS

use_pulseaudio should be false when use_cras is true.

"gn help declare_args" says:
  - Any code inside of the declare_args block will see the default
    values of previous variables defined in the block rather than
    the user-overridden value.

BUG=433082,561142

Committed: https://crrev.com/55cb6ac985369376c823de679a19a93b4b28e275
Cr-Commit-Position: refs/heads/master@{#374306}
==========

[commit-bot: I haz the power, 2016-02-09 04:38:34]

Patchset 1 (id:??) landed as
https://crrev.com/55cb6ac985369376c823de679a19a93b4b28e275
Cr-Commit-Position: refs/heads/master@{#374306}