Make use of ElapsedTimer API for the 'gen' command.

Make use of ElapsedTimer API for the 'gen' command.

BUG=None
TEST=run ./out/Default/gn, it should reporte the elapsed time without no
regressions.
R=brettw@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=243888

[brettw, 2014-01-08 05:21:43]

command_gyp.cc has almost the same code. Want to change that too? LGTM with
that.

[tfarina, 2014-01-09 01:12:24]

On 2014/01/08 05:21:43, brettw wrote:
> command_gyp.cc has almost the same code. Want to change that too? LGTM with
> that.

For sure, changed command_gyp.cc as well.

Thanks Brett!

[commit-bot: I haz the power, 2014-01-09 01:13:32]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tfarina@chromium.org/124803002/100001

[commit-bot: I haz the power, 2014-01-09 04:45:42]

Retried try job too often on win_rel for step(s) browser_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[commit-bot: I haz the power, 2014-01-09 12:51:10]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tfarina@chromium.org/124803002/100001

[commit-bot: I haz the power, 2014-01-09 14:10:11]

Change committed as 243888