Remove an obsolete comment.

Remove an obsolete comment.

The code this is referring to has moved. It's now checked as part of testing
whether metrics reporting is enabled, internally to the metrics code.

BUG=none
TEST=none
R=asvitkine@chromium.org
TBR=thestig@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272525

[Alexei Svitkine (slow), 2014-05-23 09:00:40]

lgtm

[commit-bot: I haz the power, 2014-05-23 09:02:29]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/isherman@chromium.org/295103010/1

[Ilya Sherman, 2014-05-23 09:23:33]

TBR Lei for removing an out-of-date comment from chrome_browser_main.cc.  [Hope
you don't mind us TBRing all of these refactoring CLs to you. :)]

[Lei Zhang, 2014-05-23 09:36:17]

lgtm

[commit-bot: I haz the power, 2014-05-23 12:30:28]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)

[commit-bot: I haz the power, 2014-05-23 14:46:10]

Change committed as 272525