Chrome Version: 69.0.3480.0 (Official Build) canary (64-bit)
OS: Chrome OS

What steps will reproduce the problem?
(1) The chrome://flags/#enable-surfaces-for-videos flag must be enabled.
(2) Go to The chrome://flags/#enable-surfaces-for-videos flag must be enabled.
(3) Click the "Toggle Picture-in-Picture" 3 times to enter, exit, and enter.

What is the expected result?
"> Window size changed to [xxx]" message should not appear as previous window was closed.

What happens instead?
"> Window size changed to [xxx]" shows up.


I believe we should unregister previous pipWindowResizeCallback when PictureInPictureWindow::OnClose() is called.

In third_party/blink/renderer/modules/picture_in_picture/picture_in_picture_controller_impl.cc

  element->GetWebMediaPlayer()->RegisterPictureInPictureWindowResizeCallback(
      WTF::BindRepeating(&PictureInPictureWindow::OnResize,
                         WrapPersistent(picture_in_picture_window_.Get())));