[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
Review URL: https://codereview.chromium.org/
990463002
Cr-Commit-Position: refs/heads/master@{#319670}