[GStreamer][WebRTC] webrtc/connection-state.html started failing afte…

…r update to 1.24.0

https://bugs.webkit.org/show_bug.cgi?id=271243
<rdar://problem/125014192>

Reviewed by Xabier Rodriguez-Calvar.

The `doneGatheringCandidates()` method is called by the PeerConnectionBackend when it's notified
from gst-webrtc that the ICE gathering is finished, so we don't need to call it ourselves. The
end-of-candidates SDP attribute shouldn't appear in the offer/answer the end-point reports either.
This is covered by the webrtc/libwebrtc/descriptionGetters.html test.

* LayoutTests/platform/glib/TestExpectations:
* Source/WebCore/Modules/mediastream/gstreamer/GStreamerMediaEndpoint.cpp:
(WebCore::fetchDescription):
(WebCore::GStreamerMediaEndpoint::doSetLocalDescription):
(WebCore::GStreamerMediaEndpoint::doSetRemoteDescription):
(WebCore::GStreamerMediaEndpoint::onIceCandidate):

Canonical link: https://commits.webkit.org/276412@main

LayoutTests/platform/glib/TestExpectations

@@ -1935,8 +1935,6 @@ fast/mediastream/microphone-interruption-and-audio-session.html [ Skip ]
 webkit.org/b/261329 webrtc/video-clone-track.html [ Failure ]
 webrtc/clone-audio-track.html [ Pass Failure ]
 
-webkit.org/b/271243 webrtc/connection-state.html [ Failure ]
-
 webkit.org/b/256758 fast/mediastream/captureStream/canvas3d.html [ Failure ]
 
 webkit.org/b/194611 http/wpt/webrtc/getUserMedia-processSwapping.html [ Failure ]

Source/WebCore/Modules/mediastream/gstreamer/GStreamerMediaEndpoint.cpp

@@ -312,6 +312,15 @@ static std::optional<std::pair<RTCSdpType, String>> fetchDescription(GstElement*
     if (!description)
         return { };
 
+    unsigned totalAttributesNumber = gst_sdp_message_attributes_len(description->sdp);
+    for (unsigned i = 0; i < totalAttributesNumber; i++) {
+        const auto attribute = gst_sdp_message_get_attribute(description->sdp, i);
+        if (!g_strcmp0(attribute->key, "end-of-candidates")) {
+            gst_sdp_message_remove_attribute(description->sdp, i);
+            break;
+        }
+    }
+
     GUniquePtr<char> sdpString(gst_sdp_message_as_text(description->sdp));
     GST_TRACE_OBJECT(webrtcBin, "%s-description SDP: %s", name, sdpString.get());
     return { { fromSessionDescriptionType(*description.get()), String::fromLatin1(sdpString.get()) } };
@@ -455,18 +464,9 @@ void GStreamerMediaEndpoint::doSetLocalDescription(const RTCSessionDescription*
             }
         }
 
-        // Notify the backend in case all m-lines of the current local description have signalled
-        // all their ICE candidates.
-        std::optional<bool> isIceGatheringComplete;
-        if (descriptions && !descriptions->currentLocalDescriptionSdp.isEmpty())
-            isIceGatheringComplete = this->isIceGatheringComplete(descriptions->currentLocalDescriptionSdp);
-
         GRefPtr<GstWebRTCSCTPTransport> transport;
         g_object_get(m_webrtcBin.get(), "sctp-transport", &transport.outPtr(), nullptr);
         m_peerConnectionBackend.setLocalDescriptionSucceeded(WTFMove(descriptions), { }, transport ? makeUnique<GStreamerSctpTransportBackend>(WTFMove(transport)) : nullptr);
-
-        if (isIceGatheringComplete && *isIceGatheringComplete)
-            m_peerConnectionBackend.doneGatheringCandidates();
     }, [protectedThis = Ref(*this), this](const GError* error) {
         if (protectedThis->isStopped())
             return;
@@ -538,18 +538,9 @@ void GStreamerMediaEndpoint::doSetRemoteDescription(const RTCSessionDescription&
             }
         }
 
-        // Notify the backend in case all m-lines of the current local description have signalled
-        // all their ICE candidates.
-        std::optional<bool> isIceGatheringComplete;
-        if (descriptions && !descriptions->currentLocalDescriptionSdp.isEmpty())
-            isIceGatheringComplete = this->isIceGatheringComplete(descriptions->currentLocalDescriptionSdp);
-
         GRefPtr<GstWebRTCSCTPTransport> transport;
         g_object_get(m_webrtcBin.get(), "sctp-transport", &transport.outPtr(), nullptr);
         m_peerConnectionBackend.setRemoteDescriptionSucceeded(WTFMove(descriptions), { }, transport ? makeUnique<GStreamerSctpTransportBackend>(WTFMove(transport)) : nullptr);
-
-        if (isIceGatheringComplete && *isIceGatheringComplete)
-            m_peerConnectionBackend.doneGatheringCandidates();
     }, [protectedThis = Ref(*this), this](const GError* error) {
         if (protectedThis->isStopped())
             return;
@@ -1504,16 +1495,10 @@ void GStreamerMediaEndpoint::onIceCandidate(guint sdpMLineIndex, gchararray cand
         return;
 
     auto candidateString = makeString(candidate);
-    if (candidateString.isEmpty()) {
-        callOnMainThread([protectedThis = Ref(*this), this] {
-            if (isStopped())
-                return;
-            // webrtcbin notifies an empty ICE candidate when gathering is complete.
-            GST_DEBUG_OBJECT(m_pipeline.get(), "Signaling end-of-candidates");
-            m_peerConnectionBackend.doneGatheringCandidates();
-        });
+
+    // webrtcbin notifies an empty ICE candidate when gathering is complete.
+    if (candidateString.isEmpty())
         return;
-    }
 
     callOnMainThread([protectedThis = Ref(*this), this, sdp = WTFMove(candidateString), sdpMLineIndex]() mutable {
         if (isStopped())