Revert "[Picture-in-Picture] Update window playback when video src changes."

This reverts commit 93488940ae5770af18ca5405395a206b426756a6.

Reason for revert: PictureInPictureWindowControllerBrowserTest.UpdateVideoSrcKeepsPictureInPictureWindowOpened is very flaky: https://crbug.com/865410

Original change's description:
> [Picture-in-Picture] Update window playback when video src changes.
> 
> This CL make sure the Picture-in-Picture window playback state is
> reflected when video src changes. It is a follow-up to
> https://chromium-review.googlesource.com/1089331
> 
> Bug: 726619
> Change-Id: Ic756c03aa023d3e4e229c7495686ea8f322503e3
> Reviewed-on: https://chromium-review.googlesource.com/1133168
> Commit-Queue: Mounir Lamouri <[email protected]>
> Reviewed-by: Dale Curtis <[email protected]>
> Reviewed-by: Matthew Wolenetz <[email protected]>
> Reviewed-by: Mounir Lamouri <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#576428}

[email protected],[email protected],[email protected],[email protected],[email protected]

Change-Id: I2b35b9ef8c119915b1c07f9f12321439c3242ab2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 726619, 865410
Reviewed-on: https://chromium-review.googlesource.com/1143324
Reviewed-by: Christian Dullweber <[email protected]>
Commit-Queue: Christian Dullweber <[email protected]>
Cr-Commit-Position: refs/heads/master@{#576454}
3 files changed