Correct values of UMA Enterprise.DevicePolicyInvalidations

Correct values of UMA Enterprise.DevicePolicyInvalidations

Enterprise.DevicePolicyInvalidations can take the values [0, 1, 3, 4],
not [0, 1, 2, 3] as erroneously specified in histograms.xml.

BUG=None
TEST=None

Committed: https://crrev.com/dff1f88779c4626d48e37ec2edb7a60b445aecdd
Cr-Commit-Position: refs/heads/master@{#324408}

[bartfab (slow), 2015-04-08 08:46:04]

bartfab@chromium.org changed reviewers:
+ asvitkine@chromium.org

[bartfab (slow), 2015-04-08 08:46:05]

Hi Alexei,

Could you have a look?

Scott, FYI.

[Alexei Svitkine (slow), 2015-04-08 14:59:20]

lgtm assuming these were always like this

[bartfab (slow), 2015-04-08 15:46:41]

On 2015/04/08 14:59:20, Alexei Svitkine wrote:
> lgtm assuming these were always like this

This is actually an interesting case. In the original code [1], committed 12
months ago, the values were:

POLICY_INVALIDATION_TYPE_NO_PAYLOAD_EXPIRED = 2
POLICY_INVALIDATION_TYPE_EXPIRED = 3

A subsequent change [2] committed 9 months ago contains a typo that changes
these values to:

POLICY_INVALIDATION_TYPE_NO_PAYLOAD_EXPIRED = 3
POLICY_INVALIDATION_TYPE_EXPIRED = 4

We can add a histogram value to cover "2" and we can fix the value of "4". But
there is no single correct value for "3," because older and newer Chrome OS
versions have different constants that map to this value :(.

Based on the UMA values we are seeing, the old Chrome OS versions that had
values 2 and 3 seem to have long gone out of use. We are only seeing 3 and 4 in
our stats.

[1]
https://codereview.chromium.org/226093005/diff/70001/components/policy/core/c...
[2]
https://codereview.chromium.org/375903002/diff/40001/components/policy/core/c...

[bartfab (slow), 2015-04-09 08:06:31]

The CQ bit was checked by bartfab@chromium.org

[commit-bot: I haz the power, 2015-04-09 08:07:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1067323002/1

[commit-bot: I haz the power, 2015-04-09 10:47:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-09 10:55:59]

Patchset 1 (id:??) landed as
https://crrev.com/dff1f88779c4626d48e37ec2edb7a60b445aecdd
Cr-Commit-Position: refs/heads/master@{#324408}