Remove old_login_managers from PasswordManager::CreatePendingLoginManagers

Remove old_login_managers from PasswordManager::CreatePendingLoginManagers

This is what CreatePendingLoginManagers currently does when trying to ensure
that a new batch of forms gets associated PasswordFormManagers:
  (1) It freezes a list of existing PasswordFormManager instances.
  (2) For every input form, if it is not already managed by a PFM from the
      frozen list, it creates a new one.

This CL removes the "freezing" part. Now all PFMs created until the point a
particular form is examined are considered. So if there was one PFM, A, before,
and two forms come in: X and Y, PasswordManager may proceed as follows:
  (a) Realise that X is not managed by A, hence creating a PFM B.
  (b) Realise that Y is not managed by A, but that it is managed by B, so no
      action is needed.

Before the CL, the code would have created another PFM C, equivalent to B,
because it would not check whether Y is managed by B.

(This is a random fix spotted when converting from ScopedVector, hence the
associated bug is about removing ScopedVector.)

BUG=555132
Committed: https://crrev.com/a95ac2ad614b60f0cc3c35c3725410dbbe0a68a6
Cr-Commit-Position: refs/heads/master@{#406252}

[vabr (Chromium), 2016-07-19 09:50:22]

The CQ bit was checked by vabr@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-19 09:50:58]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[vabr (Chromium), 2016-07-19 10:02:33]

The CQ bit was checked by vabr@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-19 10:02:52]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[vabr (Chromium), 2016-07-19 10:31:08]

vabr@chromium.org changed reviewers:
+ vasilii@chromium.org

[vabr (Chromium), 2016-07-19 10:31:09]

Hi Vasilii,

Does this look sensible to you?

Cheers,
Vaclav

[commit-bot: I haz the power, 2016-07-19 10:46:19]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-19 10:46:20]

Dry run: This issue passed the CQ dry run.

[vasilii, 2016-07-19 12:27:48]

lgtm

[vabr (Chromium), 2016-07-19 12:28:05]

The CQ bit was checked by vabr@chromium.org

[commit-bot: I haz the power, 2016-07-19 12:28:18]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-19 12:32:18]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-07-19 12:33:58]

Description was changed from

==========
Remove old_login_managers from PasswordManager::CreatePendingLoginManagers

This is what CreatePendingLoginManagers currently does when trying to ensure
that a new batch of forms gets associated PasswordFormManagers:
  (1) It freezes a list of existing PasswordFormManager instances.
  (2) For every input form, if it is not already managed by a PFM from the
      frozen list, it creates a new one.

This CL removes the "freezing" part. Now all PFMs created until the point a
particular form is examined are considered. So if there was one PFM, A, before,
and two forms come in: X and Y, PasswordManager may proceed as follows:
  (a) Realise that X is not managed by A, hence creating a PFM B.
  (b) Realise that Y is not managed by A, but that it is managed by B, so no
      action is needed.

Before the CL, the code would have created another PFM C, equivalent to B,
because it would not check whether Y is managed by B.

(This is a random fix spotted when converting from ScopedVector, hence the
associated bug is about removing ScopedVector.)

BUG=555132
==========

to

==========
Remove old_login_managers from PasswordManager::CreatePendingLoginManagers

This is what CreatePendingLoginManagers currently does when trying to ensure
that a new batch of forms gets associated PasswordFormManagers:
  (1) It freezes a list of existing PasswordFormManager instances.
  (2) For every input form, if it is not already managed by a PFM from the
      frozen list, it creates a new one.

This CL removes the "freezing" part. Now all PFMs created until the point a
particular form is examined are considered. So if there was one PFM, A, before,
and two forms come in: X and Y, PasswordManager may proceed as follows:
  (a) Realise that X is not managed by A, hence creating a PFM B.
  (b) Realise that Y is not managed by A, but that it is managed by B, so no
      action is needed.

Before the CL, the code would have created another PFM C, equivalent to B,
because it would not check whether Y is managed by B.

(This is a random fix spotted when converting from ScopedVector, hence the
associated bug is about removing ScopedVector.)

BUG=555132

Committed: https://crrev.com/a95ac2ad614b60f0cc3c35c3725410dbbe0a68a6
Cr-Commit-Position: refs/heads/master@{#406252}
==========

[commit-bot: I haz the power, 2016-07-19 12:33:59]

Patchset 2 (id:??) landed as
https://crrev.com/a95ac2ad614b60f0cc3c35c3725410dbbe0a68a6
Cr-Commit-Position: refs/heads/master@{#406252}