Keep all references to kInstallDate inside components/metrics/

Keep all references to kInstallDate inside components/metrics/

Follow-up to https://codereview.chromium.org/370813003/ as per request.

BUG=391338
TEST=kInstallDate is still set on startup when it wasn't previously set (and no backup is present in registry)

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283467

[gab, 2014-07-15 22:12:52]

As requested post-commit in https://codereview.chromium.org/370813003/

[Alexei Svitkine (slow), 2014-07-15 23:00:42]

LGTM, thanks!

[gab, 2014-07-15 23:59:45]

The CQ bit was checked by gab@chromium.org

[commit-bot: I haz the power, 2014-07-16 00:02:44]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/gab@chromium.org/396753005/1

[commit-bot: I haz the power, 2014-07-16 11:22:50]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  chromium_presubmit on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/chromium_presubmit/bu...)

[commit-bot: I haz the power, 2014-07-16 11:26:31]

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

[commit-bot: I haz the power, 2014-07-16 11:26:33]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/chromium_presubmit/bu...)

[gab, 2014-07-16 14:25:37]

@thestig for chrome_browser_main.cc (please CQ if it LGTY)

Thanks!
Gab

[Lei Zhang, 2014-07-16 18:07:46]

lgtm

stampy stamp

[commit-bot: I haz the power, 2014-07-16 19:14:39]

Change committed as 283467