dougarnett@, please coordinate with robertogden@ and bustamante@ to determine a suitable test, and then we can assign someone to implement.

Btw, I recently noticed we do happen to have some test coverage currently with PreviewsBrowserTest::NoScriptPreviewsDisabled due to a crashing bug with PreviewsInfoBar on Mac platform. When the test runs on mac trybot, it will crash and fail if PreviewInfoBar triggered. Not exactly what we want, but an interesting side effect.

Functionally what I think we want is:
  1. Enable DataSaver and all preview types
  2. Have fast network connection (eg, force ECT to 4G)
  3. Do HTTP navigation (which will get proxy request headers set)
  4. Verify page load succeeds without showing info bar

Secondarily, we could also test an HTTP->HTTPS navigation as well.

ryansturm mentioned there's a histogram that reports when the infobar shows up. Using that in a ChromeDriver test seems like a much more reliable and visible test than UIAutomator. I'd vote strongly in favor of that 

Yes, a much better idea. I will look for opportunity to try to add checks to some existing chromedriver tests - both were info bar expected and where not expected.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4f9d384de8e2adab6035be43a7480ab5982c916d

commit 4f9d384de8e2adab6035be43a7480ab5982c916d
Author: Doug Arnett <dougarnett@chromium.org>
Date: Fri Dec 01 21:22:25 2017

Adds InforBar histogram checks for LitePage integration tests

Adds both a positive check and negative check.

Bug:  787185 
Change-Id: I4a5c9c450d4500604bbfc4690f7ef6fcc643c87a
Reviewed-on: https://chromium-review.googlesource.com/804198
Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Commit-Queue: Doug Arnett <dougarnett@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521066}
[modify] https://crrev.com/4f9d384de8e2adab6035be43a7480ab5982c916d/tools/chrome_proxy/webdriver/lite_page.py