Add macro definition __CHROMEOS__ for ChromeOS builds in GYP.

Add macro definition __CHROMEOS__ for ChromeOS builds in GYP.

This is needed for clients that need to address some special
behaviors of ChromeOS.

This is intended to be a cherry-pick for older releases, where
GYP is used

BUG=chromium:628040
Committed: https://crrev.com/b655d0a1b0ea8cf0dc8e29ee650c8a55b79337d1
Cr-Commit-Position: refs/heads/master@{#407630}

[laszio, 2016-07-25 22:09:30]

laszio@google.com changed reviewers:
+ laszio@google.com, llozano@chromium.org, mark@chromium.org

[laszio, 2016-07-25 22:33:39]

laszio@google.com changed reviewers:
+ thestig@chromium.org

[laszio, 2016-07-25 22:38:16]

The CQ bit was checked by laszio@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-07-25 22:38:47]

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

[Lei Zhang, 2016-07-25 22:43:18]

lgtm

[commit-bot: I haz the power, 2016-07-25 23:18:37]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-25 23:18:38]

Dry run: This issue passed the CQ dry run.

[laszio, 2016-07-25 23:25:14]

The CQ bit was checked by laszio@google.com

[commit-bot: I haz the power, 2016-07-25 23:26:11]

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, 2016-07-25 23:30:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-25 23:33:20]

Description was changed from

==========
Add macro definition __CHROMEOS__ for ChromeOS builds in GYP.

This is needed for clients that need to address some special
behaviors of ChromeOS.

This is intended to be a cherry-pick for older releases, where
GYP is used

BUG=chromium:628040
==========

to

==========
Add macro definition __CHROMEOS__ for ChromeOS builds in GYP.

This is needed for clients that need to address some special
behaviors of ChromeOS.

This is intended to be a cherry-pick for older releases, where
GYP is used

BUG=chromium:628040

Committed: https://crrev.com/b655d0a1b0ea8cf0dc8e29ee650c8a55b79337d1
Cr-Commit-Position: refs/heads/master@{#407630}
==========

[commit-bot: I haz the power, 2016-07-25 23:33:21]

Patchset 1 (id:??) landed as
https://crrev.com/b655d0a1b0ea8cf0dc8e29ee650c8a55b79337d1
Cr-Commit-Position: refs/heads/master@{#407630}