[Password Manager] Extract some methods of SavePasswordInfobarDelegate to separate class.

[Password Manager] Extract some methods of SavePasswordInfobarDelegate to separate class.

Some methods of the SavePasswordInfobarDelegate can be reused in other
password manager related delegates in the future, e.g. delegate for the
update password infobar.
So this patch introduces the base class for the password manager
infobar's delegates.

BUG=359315, 532876
Committed: https://crrev.com/d2f1f4bed6f43f5bcf16f242c83b9b6048fdf9dc
Cr-Commit-Position: refs/heads/master@{#351069}

[melandory, 2015-09-02 11:58:54]

Patchset #1 (id:1) has been deleted

[melandory, 2015-09-28 11:33:23]

Patchset #5 (id:100001) has been deleted

[melandory, 2015-09-28 11:33:29]

Patchset #4 (id:80001) has been deleted

[melandory, 2015-09-28 11:33:35]

Patchset #3 (id:60001) has been deleted

[melandory, 2015-09-28 11:39:04]

melandory@chromium.org changed reviewers:
+ dvadym@chromium.org

[melandory, 2015-09-28 11:39:05]

Hey Vadym,

PTAL. Thanks!

[dvadym, 2015-09-28 14:02:05]

On 2015/09/28 11:39:05, melandory wrote:
> Hey Vadym,
> 
> PTAL. Thanks!

LGTM

[melandory, 2015-09-28 14:11:58]

The CQ bit was checked by melandory@chromium.org

[commit-bot: I haz the power, 2015-09-28 14:12:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1313363004/120001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1313363004/120001

[commit-bot: I haz the power, 2015-09-28 14:59:26]

Committed patchset #3 (id:120001)

[commit-bot: I haz the power, 2015-09-28 15:00:03]

Patchset 3 (id:??) landed as
https://crrev.com/d2f1f4bed6f43f5bcf16f242c83b9b6048fdf9dc
Cr-Commit-Position: refs/heads/master@{#351069}