[Picture-in-Picture] Close window when user navigates away.

Picture-in-Picture window should be closed after navigating away while
same document navigations should not close Picture-in-Picture window.

Bug: 726619
Change-Id: Ibd07dfd2f62af23573ab2221138b4776df26f22c
Reviewed-on: https://chromium-review.googlesource.com/1137818
Commit-Queue: Fran├žois Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575349}
3 files changed