[GStreamer][Broadcom] fix incorrect casting of GstGhostPad to GstElement

https://bugs.webkit.org/show_bug.cgi?id=305788

Reviewed by Xabier Rodriguez-Calvar.

The problem is observed when brcm audio/video filters are plugged into
the "inner-parser" in WebKitThunderParser.
GStreamerQuirkBroadcomBase::setupBufferingPercentageCorrection() tries
and fails to cast GstGhostPad to GstElement. The
gst_pad_get_parent_element() method fits better for the use case.

Also, this change disables the correction of buffering percentage for
MSE and MediaStream playbacks, since it only makes sense for regular
playback.

Original author: Eugene Mutavchi <Ievgen_Mutavchi@comcast.com>

* Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamer.cpp:
(WebCore::MediaPlayerPrivateGStreamer::handleMessage): Only do buffering percentage correction on regular playback (not MediaStream, not MSE).
* Source/WebCore/platform/gstreamer/GStreamerQuirkBroadcomBase.cpp:
(WebCore::GStreamerQuirkBroadcomBase::setupBufferingPercentageCorrection const): Use gst_pad_get_parent_element() instead of gst_pad_get_parent(), since it's more robust against the case when the parent isn't a GstElement.

Canonical link: https://commits.webkit.org/305877@main

Author: emutavchi

Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamer.cpp

@@ -2166,7 +2166,7 @@ void MediaPlayerPrivateGStreamer::handleMessage(GstMessage* message)
             }
         }
 
-        if (quirksManager.isEnabled() && quirksManager.needsBufferingPercentageCorrection())
+        if (quirksManager.isEnabled() && quirksManager.needsBufferingPercentageCorrection() && !isMediaSource() && !isMediaStreamPlayer())
             quirksManager.setupBufferingPercentageCorrection(this, currentState, newState, GRefPtr<GstElement>(GST_ELEMENT(GST_MESSAGE_SRC(message))));
 
         if (!messageSourceIsPlaybin || m_isDelayingLoad)

Source/WebCore/platform/gstreamer/GStreamerQuirkBroadcomBase.cpp

@@ -141,7 +141,7 @@ void GStreamerQuirkBroadcomBase::setupBufferingPercentageCorrection(MediaPlayerP
                 GRefPtr<GstPad> peerSrcPad = adoptGRef(gst_pad_get_peer(sinkPad));
                 if (!peerSrcPad)
                     continue; // And end the loop, because there's only one srcpad.
-                GRefPtr<GstElement> peerElement = adoptGRef(GST_ELEMENT(gst_pad_get_parent(peerSrcPad.get())));
+                GRefPtr<GstElement> peerElement = adoptGRef(gst_pad_get_parent_element(peerSrcPad.get()));
 
                 // If it's NOT a multiqueue, it's probably a parser like aacparse. We try to traverse before it.
                 if (peerElement && g_strcmp0(G_OBJECT_TYPE_NAME(element.get()), "GstMultiQueue")) {
@@ -150,7 +150,7 @@ void GStreamerQuirkBroadcomBase::setupBufferingPercentageCorrection(MediaPlayerP
                         if (!peerSrcPad)
                             continue; // And end the loop.
                         // Now we hopefully have peerElement pointing to the multiqueue.
-                        peerElement = adoptGRef(GST_ELEMENT(gst_pad_get_parent(peerSrcPad.get())));
+                        peerElement = adoptGRef(gst_pad_get_parent_element(peerSrcPad.get()));
                         break;
                     }
                 }