cros: Migrate discover away from prefixed-based JS calls

Bug: 908498
Change-Id: I763088c5a8f6eb065c563ae269e6ec24955aa1fc
Reviewed-on: https://chromium-review.googlesource.com/c/1351688
Commit-Queue: Jacob Dufault <jdufault@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625363}
3 files changed