Expose CC.host_wrapper and CXX.host_wrapper.

Expose CC.host_wrapper and CXX.host_wrapper.

Currently, the gyp variables CC_wrapper and CXX_wrapper can be set in
the chromium.gyp_env file. However, the host compiler wrapper variable
cannot. By exposing this variable, embedders can more easily
use tools like ccache or icecream when developing for android.

BUG=471340
Committed: https://crrev.com/73e65d4adbbc1cc83f7e59b2dfe60107c2dd186e
Cr-Commit-Position: refs/heads/master@{#323557}

[cwgreene, 2015-04-02 17:26:39]

cwgreene@amazon.com changed reviewers:
+ dpranke@chromium.org

[cwgreene, 2015-04-02 17:27:18]

On 2015/04/02 17:26:39, cwgreene wrote:
> mailto:cwgreene@amazon.com changed reviewers:
> + mailto:dpranke@chromium.org

PTAL. The patches are identical, sorry about that.

[Dirk Pranke, 2015-04-02 17:41:41]

lgtm

[cwgreene, 2015-04-02 17:56:15]

The CQ bit was checked by cwgreene@amazon.com

[commit-bot: I haz the power, 2015-04-02 17:57:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1044423005/20001

[commit-bot: I haz the power, 2015-04-02 20:42:15]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-03 20:28:51]

Patchset 2 (id:??) landed as
https://crrev.com/73e65d4adbbc1cc83f7e59b2dfe60107c2dd186e
Cr-Commit-Position: refs/heads/master@{#323557}