Trigger element fullscreen video extraction after the seeked event

https://bugs.webkit.org/show_bug.cgi?id=241053

Reviewed by Devin Rousso.

* Source/WebKit/WebProcess/FullScreen/WebFullScreenManager.cpp:
(WebKit::WebFullScreenManager::handleEvent):
(WebKit::WebFullScreenManager::setMainVideoElement):

Canonical link: https://commits.webkit.org/251090@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@294986 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebKit/WebProcess/FullScreen/WebFullScreenManager.cpp

@@ -387,7 +387,8 @@ void WebFullScreenManager::handleEvent(WebCore::ScriptExecutionContext& context,
     }
 
     if (targetElement == m_mainVideoElement.get()) {
-        if (m_mainVideoElement && m_mainVideoElement->paused())
+        auto& targetVideoElement = downcast<HTMLVideoElement>(*targetElement);
+        if (targetVideoElement.paused() && !targetVideoElement.seeking())
             scheduleMainVideoElementExtraction();
         else
             endMainVideoElementExtractionIfNeeded();
@@ -439,6 +440,7 @@ void WebFullScreenManager::setMainVideoElement(RefPtr<WebCore::HTMLVideoElement>
 
     static NeverDestroyed eventsToObserve = std::array {
         WebCore::eventNames().seekingEvent,
+        WebCore::eventNames().seekedEvent,
         WebCore::eventNames().playingEvent,
         WebCore::eventNames().pauseEvent,
     };