Do not activate windows when showing chooser bubbles.

Activating windows allows popunders, and is disallowed in Chromium.
Ensure that we do not activate a window when we show a chooser
bubble.

BUG=838314

Change-Id: I052adb7b4bc37a439961059ab95670edcf85cd69
Reviewed-on: https://chromium-review.googlesource.com/1059451
Commit-Queue: Ben Wells <benwells@chromium.org>
Reviewed-by: Ben Wells <benwells@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559384}
1 file changed