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This creates an end-to-end connection from the navigation stack into the
new third-party JS lib which will handle the highlighting/scrolling in
the page.

Change-Id: I95d2a0e89387708d573bfab4617fa5ff34f516c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2354605
Commit-Queue: Tommy Martino <tmartino@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798300}