When we upgrade, discard all uploadable stats, including old logs...

When we upgrade, discard all uploadable stats, including old logs

We already discard all stability info when we do an upgrade to a new
version, as there is less concern about stats from old versions. This
change just adds the list of "old logs" (gathered in previous sessions,
presumably with an old version) to the list of data that is discarded.

BUG=14657
r=evanm

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=18794

[Evan Martin, 2009-06-19 05:14:22]

LGTM

http://codereview.chromium.org/131089/diff/1/2
File chrome/browser/metrics/metrics_service.cc (right):

http://codereview.chromium.org/131089/diff/1/2#newcode381
Line 381: prefs::kMetricsOngoingLogs);
Can these ever be NULL?  Just want you to be sure.

[jar (doing other things), 2009-06-19 06:07:19]

http://codereview.chromium.org/131089/diff/1/2
File chrome/browser/metrics/metrics_service.cc (right):

http://codereview.chromium.org/131089/diff/1/2#newcode381
Line 381: prefs::kMetricsOngoingLogs);
On 2009/06/19 05:14:22, Evan Martin wrote:
> Can these ever be NULL?  Just want you to be sure.

It is guaranteed to be non-NULL so long as the pref is registered.  It will
create a dictionary if one does not exist, or return the existing dictionary.

All prefs are registered in a local function MetricsService::RegisterPrefs()
which is one of many module initialization functions called from
RegisterAllPrefs() in browser_prefs.cc.   Bottom line: The prefs are registered
whether metrics services are used or not, and hence this return value is always
non-NULL.