Add the Sync.Attachments.StoreInitResult histogram.

Add the Sync.Attachments.StoreInitResult histogram.

BUG=436134
Committed: https://crrev.com/771c7499315027a9975160aa8040d6d8e63a7c63
Cr-Commit-Position: refs/heads/master@{#307943}

[maxbogue, 2014-12-08 22:41:02]

maxbogue@chromium.org changed reviewers:
+ asvitkine@chromium.org, maniscalco@chromium.org, pavely@chromium.org

[maxbogue, 2014-12-08 22:41:03]

PTAL. I made RESULT_SIZE a constant instead of an enum member because there are
many switch statements that broke when I added it to the enum and it felt wrong
to add default clauses to them.

[Alexei Svitkine (slow), 2014-12-09 17:53:42]

lgtm

[pavely, 2014-12-10 22:48:34]

https://codereview.chromium.org/751313005/diff/20001/sync/api/attachments/att...
File sync/api/attachments/attachment_store.h (right):

https://codereview.chromium.org/751313005/diff/20001/sync/api/attachments/att...
sync/api/attachments/attachment_store.h:44: const int RESULT_SIZE = 3; // Size
of the Result enum; used for histograms.
Ok, let's assign explicit values to constants so that reordering and deletion
doesn't affect histogram and set RESULT_SIZE to 10 so that it covers future
possible values.

[maxbogue, 2014-12-11 00:37:33]

On 2014/12/10 22:48:34, pavely wrote:
>
https://codereview.chromium.org/751313005/diff/20001/sync/api/attachments/att...
> File sync/api/attachments/attachment_store.h (right):
> 
>
https://codereview.chromium.org/751313005/diff/20001/sync/api/attachments/att...
> sync/api/attachments/attachment_store.h:44: const int RESULT_SIZE = 3; // Size
> of the Result enum; used for histograms.
> Ok, let's assign explicit values to constants so that reordering and deletion
> doesn't affect histogram and set RESULT_SIZE to 10 so that it covers future
> possible values.

Done, PTAL.

[pavely, 2014-12-11 00:41:57]

lgtm

[maniscalco, 2014-12-11 17:03:47]

lgtm

[maxbogue, 2014-12-11 18:12:04]

The CQ bit was checked by maxbogue@chromium.org

[commit-bot: I haz the power, 2014-12-11 18:13:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/751313005/40001

[commit-bot: I haz the power, 2014-12-11 19:14:12]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2014-12-11 19:15:03]

Patchset 3 (id:??) landed as
https://crrev.com/771c7499315027a9975160aa8040d6d8e63a7c63
Cr-Commit-Position: refs/heads/master@{#307943}