Add unit tests for Autofill automation EG actions, including waitFor and click.

Adds automation_action_egtest.mm, which is responsible for unit testing individual
Autofill automation actions. It does so by hosting a test web page (I reuse
credit_card_upload_form_address_and_cc.html, which is already used for autofill),
performing a minimal amount of automation actions, and using JS to verify result.

I also add a little functionality to credit_card_upload_form_address_and_cc.html
to make the waitFor test more substantial.

I confirmed both tests pass before uploading the CL.

so I will make one for this one in the morning

Bug: None, but I said I would make an umbrella bug for the first CL, and didn't,
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: I1ce3a185fc9b10ab3b8f352c8c22a092ae877eff
Reviewed-on: https://chromium-review.googlesource.com/1195144
Commit-Queue: ericale <[email protected]>
Reviewed-by: Eric Noyau <[email protected]>
Cr-Commit-Position: refs/heads/master@{#587462}
4 files changed