Cherry-pick dd4b8a6a214f. rdar://163974170

    [visionOS] Chrome missing after exiting spatial fullscreen on uploadvr.com
    https://bugs.webkit.org/show_bug.cgi?id=301851
    rdar://159979195

    Reviewed by Jer Noble.

    The following order of events can cause window chrome to be hidden in the WKWebView's window after
    watching a video in spatial fullscreen:

    1. The user enters element fullscreen; WKFullscreenWindowController saves the state of the
       WKWebView window’s chrome, then hides the chrome.
    2. The user enters spatial fullscreen; LinearMediaKit saves the state of the WKWebView window’s
       chrome, then hides the chrome again.
    3. The website calls document.exitFullscreen(); WKFullscreenWindowController closes the element
       fullscreen window and restores the saved state of the WKWebView window’s chrome.
    4. The user exits spatial fullscreen; LinearMediaKit restores the saved state of the WKWebView
       window’s chrome.

    Since when LinearMediaKit saved the state of the window chrome it was hidden, it is restored to a
    hidden state in (4) even though it was previously made visible in (3).

    Resolved this by checking if the native fullscreen-eligible video is in fullscreen when exiting
    element fullscreen. If it is, WKFullscreenWindowController retains _parentWindowState so that it
    can be later restored when native fullscreen exits. Made WKFullscreenWindowController a client of
    the VideoPresentationModel that enters spatial fullscreen (or any other native fullscreen mode) so
    that it can learn when the user exits native fullscreen (which required adding a new
    VideoPresentationModelClient callback). and when they do, used _parentWindowState to restore window
    chrome (as well as other state like ornaments and resizing behavior).

    * Source/WebCore/platform/cocoa/VideoPresentationModel.h:
    (WebCore::VideoPresentationModelClient::fullscreenModeChanged):
    * Source/WebCore/platform/cocoa/VideoPresentationModelVideoElement.h:
    * Source/WebCore/platform/cocoa/VideoPresentationModelVideoElement.mm:
    (WebCore::VideoPresentationModelVideoElement::fullscreenModeChanged):
    * Source/WebCore/platform/ios/VideoPresentationInterfaceIOS.h:
    * Source/WebCore/platform/ios/VideoPresentationInterfaceIOS.mm:
    (WebCore::VideoPresentationInterfaceIOS::enterFullscreenHandler):
    (WebCore::VideoPresentationInterfaceIOS::exitFullscreenHandler):
    (WebCore::VideoPresentationInterfaceIOS::didStartPictureInPicture):
    (WebCore::VideoPresentationInterfaceIOS::failedToStartPictureInPicture):
    (WebCore::VideoPresentationInterfaceIOS::didStopPictureInPicture):
    (WebCore::VideoPresentationInterfaceIOS::setMode):
    (WebCore::VideoPresentationInterfaceIOS::clearMode):
    * Source/WebCore/platform/ios/WebVideoFullscreenControllerAVKit.mm:
    (VideoFullscreenControllerContext::fullscreenModeChanged):
    * Source/WebKit/Platform/ios/VideoPresentationInterfaceLMK.mm:
    (WebKit::VideoPresentationInterfaceLMK::swapFullscreenModesWith):
    * Source/WebKit/UIProcess/Cocoa/VideoPresentationManagerProxy.h:
    * Source/WebKit/UIProcess/Cocoa/VideoPresentationManagerProxy.mm:
    (WebKit::VideoPresentationModelContext::fullscreenModeChanged):
    (WebKit::VideoPresentationManagerProxy::setVideoFullscreenMode):
    (WebKit::VideoPresentationManagerProxy::didCleanupFullscreen):
    * Source/WebKit/UIProcess/ios/fullscreen/WKFullScreenViewController.h:
    * Source/WebKit/UIProcess/ios/fullscreen/WKFullScreenViewController.mm:
    (-[WKFullScreenViewController invalidate]):
    (-[WKFullScreenViewController _bestVideoPresentationInterface]):
    (-[WKFullScreenViewController configureEnvironmentPickerOrFullscreenVideoButtonView]):
    (-[WKFullScreenViewController _playbackSessionInterface]):
    (-[WKFullScreenViewController _enterVideoFullscreenAction:]):
    * Source/WebKit/UIProcess/ios/fullscreen/WKFullScreenWindowControllerIOS.h:
    * Source/WebKit/UIProcess/ios/fullscreen/WKFullScreenWindowControllerIOS.mm:
    (-[WKFullScreenWindowController initWithWebView:]):
    (-[WKFullScreenWindowController _completedExitFullScreen:]):
    (-[WKFullScreenWindowController _isBestVideoInFullScreen]):
    (-[WKFullScreenWindowController _shouldShowOrnaments]):
    (-[WKFullScreenWindowController _performSpatialFullScreenTransition:completionHandler:]):
    (-[WKFullScreenWindowController bestVideoFullscreenModeChanged]):
    (-[WKFullScreenWindowController fullScreenViewControllerDidInvalidate:]):
    (-[WKFullScreenWindowController fullScreenViewController:bestVideoPresentationInterfaceDidChange:]):
    * Source/WebKit/WebProcess/cocoa/VideoPresentationManager.mm:
    (WebKit::VideoPresentationManager::fullscreenModeChanged):

    Canonical link: https://commits.webkit.org/302506@main

Identifier: 301765.263@safari-7623-branch