Handle duplicate password sync nodes

Handle duplicate password sync nodes

If the PasswordStore is asked to add an entry that already exists it
will overwrite the existing entry.  When this happens, it will report a
PasswordStoreChange::ADD event, much like it would had the original
entry not existed.  This confuses the PasswordChangeProcessor which
assumes that an ADD event implies that the added item did not previously
exist.

This change works around the issue by allowing the password change
processor to try to update an existing node in the event that the
creation of a new node fails.  This allows it to handle the case where a
it receives an ADD event for an existing node.

A better solution would be to have the PasswordStore to always return an
UPDATE event in cases where the node being updated already exists.  If
that solution were implemented the PasswordChangeProcessor would be
right to report an UnrecoverableError if it is unable to create a new
sync node in response to an ADD event.

BUG=87855
TEST=See repro steps in crbug.com/87855, crbug.com/103455


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=113888

[rlarocque, 2011-12-08 00:10:07]

This is a workaround for issues 87855 and 103455.  We can remove this code when
the PasswordStore is able to guarantee we only see ADD changes for nodes that
did not previously exist.

[lipalani1, 2011-12-08 00:13:58]

LGTM!!
Deja vu! I think I put in a similar fix while ago but then reverted in the hopes
that the password team would fix this :)

[Mike Mammarella, 2011-12-08 04:32:04]

LGTM, thanks!

http://codereview.chromium.org/8862005/diff/1/chrome/browser/sync/glue/passwo...
File chrome/browser/sync/glue/password_change_processor.cc (right):

http://codereview.chromium.org/8862005/diff/1/chrome/browser/sync/glue/passwo...
chrome/browser/sync/glue/password_change_processor.cc:108: "Unable to create or
lookup password node");
Grammar nit: "look up" is two words as a verb.

[rlarocque, 2011-12-09 18:53:42]

I'll let the trybots have another run at this then hit the commit button this
afternoon.

http://codereview.chromium.org/8862005/diff/1/chrome/browser/sync/glue/passwo...
File chrome/browser/sync/glue/password_change_processor.cc (right):

http://codereview.chromium.org/8862005/diff/1/chrome/browser/sync/glue/passwo...
chrome/browser/sync/glue/password_change_processor.cc:108: "Unable to create or
lookup password node");
On 2011/12/08 04:32:04, Mike Mammarella wrote:
> Grammar nit: "look up" is two words as a verb.

Done.

[commit-bot: I haz the power, 2011-12-09 21:11:44]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rlarocque@chromium.org/8862005/4001

[commit-bot: I haz the power, 2011-12-10 00:12:44]

Change committed as 113888