Fix crash when HTMLMediaElement::exitFullscreen is called on a video

element which is not currently full screen
https://bugs.webkit.org/show_bug.cgi?id=255970
rdar://108489504

Reviewed by Jer Noble.

This change fixes an issue where exitFullScreen is called on video, but
the current full screen element is div, due to which we end up
scheduling the webkitendfullscreenEvent event for video, which trips
over an assertion.

* LayoutTests/fullscreen/exit-full-screen-video-crash-expected.txt: Added.
* LayoutTests/fullscreen/exit-full-screen-video-crash.html: Added.
* Source/WebKit/WebProcess/cocoa/VideoFullscreenManager.mm:
(WebKit::VideoFullscreenManager::exitVideoFullscreenForVideoElement):
(WebKit::VideoFullscreenManager::exitVideoFullscreenToModeWithoutAnimation):

Originally-landed-as: 259548.703@safari-7615-branch (0ffc79d). rdar://113167859
Canonical link: https://commits.webkit.org/266584@main

LayoutTests/TestExpectations

@@ -6552,3 +6552,5 @@ webkit.org/b/257904 http/tests/site-isolation/basic-iframe.html [ Skip ]
 
 # Only some OSes have support for auto word breaking.
 imported/w3c/web-platform-tests/css/css-text/word-break/auto [ Pass Failure ImageOnlyFailure ]
+
+webkit.org/b/255970 [ Debug ] fullscreen/exit-full-screen-video-crash.html [ Crash ]

LayoutTests/fullscreen/exit-full-screen-video-crash-expected.txt

@@ -0,0 +1 @@
+PASS if no crash

LayoutTests/fullscreen/exit-full-screen-video-crash.html

@@ -0,0 +1,17 @@
+<script>
+  onload = async () => {
+    if (window.testRunner)
+      testRunner.dumpAsText();
+    internals.withUserGesture(() => {});
+    let video0 = document.createElement('video');
+    video0.src = 'data:video/mp4;';
+    document.body.append(video0);
+    $vm.print(await video0.requestFullscreen());
+    navigator.mediaSession.callActionHandler({action: 'play'});
+    let div0 = document.createElement('div');
+    video0.append(div0);
+    $vm.print(await div0.requestFullscreen());
+    video0.webkitSetPresentationMode('inline');
+    document.body.innerHTML = 'PASS if no crash';
+  };
+</script>

LayoutTests/platform/gtk/fullscreen/exit-full-screen-video-crash-expected.txt

@@ -0,0 +1,2 @@
+CONSOLE MESSAGE: Unhandled Promise Rejection: TypeError: video0.webkitSetPresentationMode is not a function. (In 'video0.webkitSetPresentationMode('inline')', 'video0.webkitSetPresentationMode' is undefined)
+

Source/WebKit/WebProcess/cocoa/VideoFullscreenManager.mm

@@ -409,9 +409,16 @@ static FloatRect inlineVideoFrame(HTMLVideoElement& element)
 void VideoFullscreenManager::exitVideoFullscreenForVideoElement(HTMLVideoElement& videoElement, CompletionHandler<void(bool)>&& completionHandler)
 {
     INFO_LOG(LOGIDENTIFIER);
+    LOG(Fullscreen, "VideoFullscreenManager::exitVideoFullscreenForVideoElement(%p)", this);
+
     ASSERT(m_page);
     ASSERT(m_videoElements.contains(videoElement));
 
+    if (!m_videoElements.contains(videoElement)) {
+        completionHandler(false);
+        return;
+    }
+
     auto contextId = m_videoElements.get(videoElement);
     auto& interface = ensureInterface(contextId);
     if (interface.animationState() != VideoFullscreenInterfaceContext::AnimationType::None) {
@@ -442,6 +449,9 @@ static FloatRect inlineVideoFrame(HTMLVideoElement& element)
     ASSERT(m_page);
     ASSERT(m_videoElements.contains(videoElement));
 
+    if (!m_videoElements.contains(videoElement))
+        return;
+
     if (m_videoElementInPictureInPicture == &videoElement)
         m_videoElementInPictureInPicture = nullptr;