[autofill] Query credit card scanning feature once per browser process.

[autofill] Query credit card scanning feature once per browser process.

Checking whether credit card scanning is possible can be an expensive
operation. The result of this call is unlikely to change during the
lifetime of a browser process. This patch will query credit card
scanning feature once when the user types in a credit card input field
for the first time. Restarting the browser process is necessary to clear
the cache.

BUG=461944
Committed: https://crrev.com/f159055ebd535230ccd05791c9852c5d558248ed
Cr-Commit-Position: refs/heads/master@{#319670}

[please use gerrit instead, 2015-03-06 23:14:51]

rouslan@chromium.org changed reviewers:
+ estade@chromium.org

[please use gerrit instead, 2015-03-06 23:14:52]

Evan, PTAL.

[Evan Stade, 2015-03-06 23:20:54]

lgtm

[please use gerrit instead, 2015-03-06 23:28:14]

The CQ bit was checked by rouslan@chromium.org

[commit-bot: I haz the power, 2015-03-06 23:28:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/990463002/1

[commit-bot: I haz the power, 2015-03-07 01:04:26]

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

[commit-bot: I haz the power, 2015-03-07 01:04:28]

Try jobs failed on following builders:
  mac_chromium_compile_dbg_ng on tryserver.chromium.mac (JOB_TIMED_OUT, no build
URL)
  mac_chromium_rel_ng on tryserver.chromium.mac (JOB_TIMED_OUT, no build URL)
Timed out jobs are not retried to avoid causing additional load on the builders
with large pending queues.

[please use gerrit instead, 2015-03-09 16:40:12]

The CQ bit was checked by rouslan@chromium.org

[commit-bot: I haz the power, 2015-03-09 16:40:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/990463002/1

[commit-bot: I haz the power, 2015-03-09 17:35:27]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-09 17:36:10]

Patchset 1 (id:??) landed as
https://crrev.com/f159055ebd535230ccd05791c9852c5d558248ed
Cr-Commit-Position: refs/heads/master@{#319670}