GitLab

created a Top Site Provider for querying SiteEngagementService

Implemented a feature flag controlled by IsOnePlatformHintsEnabled()
for enabling OnePlatform API and requests.

Implemented the Top Site Provider inference and implementation for
querying the Site Engagement Service to provide the list of top hosts
for the OnePlatform to perform the Hints Request to the Cacao server.

Updated the unittests for Previews Optimization Guide and Previews
Decider Impl to include the TopSiteProvider being passed.

Wrote a PreviewsOnePlatformHintBrowserTest for confirming the feature
flag and code path is executed safely.


Bug: 932707
Change-Id: I2d1a048a86e8c8b33c98c07312cc77bafa9b52dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1478362
Commit-Queue: Michael Crouse <mcrouse@chromium.org>
Auto-Submit: Michael Crouse <mcrouse@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638654}