Copy build changes to compile mojo::AsyncWaiter to the chromium repo.

Copy build changes to compile mojo::AsyncWaiter to the chromium repo.

mojo::AsyncWaiter was added to mojo/public/cpp/environment in
https://github.com/domokit/mojo/commit/2b6c27fbbe9b704a77e977615b945f364bf520ca
and was rolled into chromium. However, the chromium environment
implementation is on mojo/environment, which is maintained independently
of the version in the mojo repo. This CL copies the mojo repo's
mojo/environment into the chromium repo so that mojo::AsyncWaiter is
usable there.

Committed: https://crrev.com/b02c427dcb9f3cfa5c84ec685e0f1d52cd8fba9f
Cr-Commit-Position: refs/heads/master@{#313859}

[Sam McNally, 2015-01-29 03:31:38]

sammc@chromium.org changed reviewers:
+ jamesr@chromium.org

[jamesr, 2015-01-29 20:11:01]

Please roll everything together - patching things piecewise  in the chromium
repo makes it really hard to understand the state of the world.

[Sam McNally, 2015-01-29 23:43:15]

On 2015/01/29 20:11:01, jamesr wrote:
> Please roll everything together - patching things piecewise  in the chromium
> repo makes it really hard to understand the state of the world.

Done, assuming you meant just mojo/environment.

[jamesr, 2015-01-29 23:44:37]

jamesr@chromium.org changed reviewers:
+ viettrungluu@chromium.org

[jamesr, 2015-01-29 23:44:38]

Oh - sorry I was confused.  This isn't a roll at all, this is code developed
independently in chromium vs mojo.  Trung should review this.

Please fix the patch description to say what you are doing here.

[viettrungluu, 2015-01-30 00:05:33]

LGTM, but:

* "However, //mojo/environment:chromium is where the files in
mojo/public/cpp/environment are built, and mojo/environment isn't rolled into
chromium." is perhaps slightly misleading/confusing.
* Obviously, as //mojo/public evolves, you'll need to update things that depend
on it. This may entail duplicating changes as done in this change, but
eventually Mojo's //mojo/environment may diverge in a way that you won't simply
be able to copy over.
* So you should really view Chromium's //mojo/environment as an independent
implementation of the //mojo/public/cpp/environment. (The Mojo public SDK
provides another implementation in //mojo/public/cpp/environment/lib, which
obviously isn't suitable for Chromium's purposes.)

[Sam McNally, 2015-01-30 01:47:18]

Updated the description to hopefully be clearer/more correct.

jamesr: PTAL

[jamesr, 2015-01-30 02:13:02]

lgtm

[Sam McNally, 2015-01-30 02:16:19]

The CQ bit was checked by sammc@chromium.org

[commit-bot: I haz the power, 2015-01-30 02:17:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/883583005/20001

[commit-bot: I haz the power, 2015-01-30 02:21:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-01-30 02:21:51]

Patchset 2 (id:??) landed as
https://crrev.com/b02c427dcb9f3cfa5c84ec685e0f1d52cd8fba9f
Cr-Commit-Position: refs/heads/master@{#313859}