Disable highlight for Previews IPH

I added a helper method for this to allow for easier changes like this
down the road, if wanted for other features.

Bug: 930877
Change-Id: Iad809f2e94e85db57e661f610ce63be9619a2dff
Reviewed-on: https://chromium-review.googlesource.com/c/1465062
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631027}
1 file changed