[Autofill Clean up] Revert changes introduced by Autocheckout to autofill

[Autofill Clean up] Revert changes introduced by Autocheckout to autofill
disabled and readonly fields. Autocheckout is deprecated.

R=isherman@chromium.org
BUG=231160
Committed: https://crrev.com/d9b040ba4ff2ff78f183816b9d0e34c5f450160c
Cr-Commit-Position: refs/heads/master@{#297015}

[ziran.sun, 2014-09-26 12:18:37]

Please review. Thanks!

[Ilya Sherman, 2014-09-26 19:15:24]

LGTM.  Thanks!

[Ilya Sherman, 2014-09-26 19:15:29]

The CQ bit was checked by isherman@chromium.org

[commit-bot: I haz the power, 2014-09-26 19:17:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/609733003/1

[commit-bot: I haz the power, 2014-09-26 20:01:48]

Committed patchset #1 (id:1) as c16f749995aaa3033e7bc82ca7b9f672ec422350

[commit-bot: I haz the power, 2014-09-26 20:02:33]

Patchset 1 (id:??) landed as
https://crrev.com/d9b040ba4ff2ff78f183816b9d0e34c5f450160c
Cr-Commit-Position: refs/heads/master@{#297015}

[Evan Stade, 2014-10-13 16:56:56]

This patch is incorrect; I believe it breaks requestAutocomplete and should be
reverted. requestAutocomplete does not care if fields are visible (in fact
fields are supposed to be hidden) or readonly (readonly is useful for stuff like
transaction details). I can't actually test if this breaks rAc at the moment
because gclient sync is taking over an hour ... :(

[Evan Stade, 2014-10-13 18:35:09]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/648243003/ by estade@chromium.org.

The reason for reverting is: these changes are still necessary for
requestAutocomplete.