Cherry-pick: Only set accessibility focus on page load for browser tabs, not web views.

Clean cherry-pick of chromium
https://crrev.com/61c6121a6cb9dc16f9786830655049d68dcde67c

BUG: 17000817

Original description:

Only set accessibility focus on page load for browser tabs, not web views.

BUG=406053

Review URL: https://codereview.chromium.org/490333002

Change-Id: I09130c2598e71c878f85a7d8bf08f2519c337639
Cr-Commit-Position: refs/heads/master@{#291713}
3 files changed