script: Move WebRTC DOM interfaces to script/dom/webrtc/ (#39023)

Move interfaces defined by the WebRTC specification to the
`script/dom/webrtc/` module from `script/dom/`.

`script/dom/rtc*.rs -> script/dom/webrtc/`

Testing: No changes, just a refactoring

Fixes (partially): #38901

Signed-off-by: Andrei Volykhin <volykhin.andrei@huawei.com>
Co-authored-by: Andrei Volykhin <volykhin.andrei@huawei.com>

components/script/dom/webrtc/rtcpeerconnection.rs

@@ -0,0 +1,858 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use std::cell::Cell;
+use std::collections::HashMap;
+use std::rc::Rc;
+
+use dom_struct::dom_struct;
+use js::rust::HandleObject;
+use servo_media::ServoMedia;
+use servo_media::streams::MediaStreamType;
+use servo_media::streams::registry::MediaStreamId;
+use servo_media::webrtc::{
+    BundlePolicy, DataChannelEvent, DataChannelId, DataChannelState, GatheringState, IceCandidate,
+    IceConnectionState, SdpType, SessionDescription, SignalingState, WebRtcController,
+    WebRtcSignaller,
+};
+
+use crate::conversions::Convert;
+use crate::dom::bindings::cell::DomRefCell;
+use crate::dom::bindings::codegen::Bindings::RTCDataChannelBinding::RTCDataChannelInit;
+use crate::dom::bindings::codegen::Bindings::RTCIceCandidateBinding::RTCIceCandidateInit;
+use crate::dom::bindings::codegen::Bindings::RTCPeerConnectionBinding::{
+    RTCAnswerOptions, RTCBundlePolicy, RTCConfiguration, RTCIceConnectionState,
+    RTCIceGatheringState, RTCOfferOptions, RTCPeerConnectionMethods, RTCRtpTransceiverInit,
+    RTCSignalingState,
+};
+use crate::dom::bindings::codegen::Bindings::RTCSessionDescriptionBinding::{
+    RTCSdpType, RTCSessionDescriptionInit, RTCSessionDescriptionMethods,
+};
+use crate::dom::bindings::codegen::UnionTypes::{MediaStreamTrackOrString, StringOrStringSequence};
+use crate::dom::bindings::error::{Error, Fallible};
+use crate::dom::bindings::inheritance::Castable;
+use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
+use crate::dom::bindings::reflector::{DomGlobal, reflect_dom_object_with_proto};
+use crate::dom::bindings::root::{Dom, DomRoot, MutNullableDom};
+use crate::dom::bindings::str::USVString;
+use crate::dom::event::{Event, EventBubbles, EventCancelable};
+use crate::dom::eventtarget::EventTarget;
+use crate::dom::mediastream::MediaStream;
+use crate::dom::mediastreamtrack::MediaStreamTrack;
+use crate::dom::promise::Promise;
+use crate::dom::rtcdatachannel::RTCDataChannel;
+use crate::dom::rtcdatachannelevent::RTCDataChannelEvent;
+use crate::dom::rtcicecandidate::RTCIceCandidate;
+use crate::dom::rtcpeerconnectioniceevent::RTCPeerConnectionIceEvent;
+use crate::dom::rtcrtptransceiver::RTCRtpTransceiver;
+use crate::dom::rtcsessiondescription::RTCSessionDescription;
+use crate::dom::rtctrackevent::RTCTrackEvent;
+use crate::dom::window::Window;
+use crate::realms::{InRealm, enter_realm};
+use crate::script_runtime::CanGc;
+use crate::task_source::SendableTaskSource;
+
+#[dom_struct]
+pub(crate) struct RTCPeerConnection {
+    eventtarget: EventTarget,
+    #[ignore_malloc_size_of = "defined in servo-media"]
+    #[no_trace]
+    controller: DomRefCell<Option<WebRtcController>>,
+    closed: Cell<bool>,
+    // Helps track state changes between the time createOffer/createAnswer
+    // is called and resolved
+    offer_answer_generation: Cell<u32>,
+    #[ignore_malloc_size_of = "promises are hard"]
+    offer_promises: DomRefCell<Vec<Rc<Promise>>>,
+    #[ignore_malloc_size_of = "promises are hard"]
+    answer_promises: DomRefCell<Vec<Rc<Promise>>>,
+    local_description: MutNullableDom<RTCSessionDescription>,
+    remote_description: MutNullableDom<RTCSessionDescription>,
+    gathering_state: Cell<RTCIceGatheringState>,
+    ice_connection_state: Cell<RTCIceConnectionState>,
+    signaling_state: Cell<RTCSignalingState>,
+    #[ignore_malloc_size_of = "defined in servo-media"]
+    data_channels: DomRefCell<HashMap<DataChannelId, Dom<RTCDataChannel>>>,
+}
+
+struct RTCSignaller {
+    trusted: Trusted<RTCPeerConnection>,
+    task_source: SendableTaskSource,
+}
+
+impl WebRtcSignaller for RTCSignaller {
+    fn on_ice_candidate(&self, _: &WebRtcController, candidate: IceCandidate) {
+        let this = self.trusted.clone();
+        self.task_source.queue(task!(on_ice_candidate: move || {
+            let this = this.root();
+            this.on_ice_candidate(candidate, CanGc::note());
+        }));
+    }
+
+    fn on_negotiation_needed(&self, _: &WebRtcController) {
+        let this = self.trusted.clone();
+        self.task_source
+            .queue(task!(on_negotiation_needed: move || {
+                let this = this.root();
+                this.on_negotiation_needed(CanGc::note());
+            }));
+    }
+
+    fn update_gathering_state(&self, state: GatheringState) {
+        let this = self.trusted.clone();
+        self.task_source
+            .queue(task!(update_gathering_state: move || {
+                let this = this.root();
+                this.update_gathering_state(state, CanGc::note());
+            }));
+    }
+
+    fn update_ice_connection_state(&self, state: IceConnectionState) {
+        let this = self.trusted.clone();
+        self.task_source
+            .queue(task!(update_ice_connection_state: move || {
+                let this = this.root();
+                this.update_ice_connection_state(state, CanGc::note());
+            }));
+    }
+
+    fn update_signaling_state(&self, state: SignalingState) {
+        let this = self.trusted.clone();
+        self.task_source
+            .queue(task!(update_signaling_state: move || {
+                let this = this.root();
+                this.update_signaling_state(state, CanGc::note());
+            }));
+    }
+
+    fn on_add_stream(&self, id: &MediaStreamId, ty: MediaStreamType) {
+        let this = self.trusted.clone();
+        let id = *id;
+        self.task_source.queue(task!(on_add_stream: move || {
+            let this = this.root();
+            this.on_add_stream(id, ty, CanGc::note());
+        }));
+    }
+
+    fn on_data_channel_event(
+        &self,
+        channel: DataChannelId,
+        event: DataChannelEvent,
+        _: &WebRtcController,
+    ) {
+        // XXX(ferjm) get label and options from channel properties.
+        let this = self.trusted.clone();
+        self.task_source
+            .queue(task!(on_data_channel_event: move || {
+                let this = this.root();
+                let global = this.global();
+                let _ac = enter_realm(&*global);
+                this.on_data_channel_event(channel, event, CanGc::note());
+            }));
+    }
+
+    fn close(&self) {
+        // do nothing
+    }
+}
+
+impl RTCPeerConnection {
+    pub(crate) fn new_inherited() -> RTCPeerConnection {
+        RTCPeerConnection {
+            eventtarget: EventTarget::new_inherited(),
+            controller: DomRefCell::new(None),
+            closed: Cell::new(false),
+            offer_answer_generation: Cell::new(0),
+            offer_promises: DomRefCell::new(vec![]),
+            answer_promises: DomRefCell::new(vec![]),
+            local_description: Default::default(),
+            remote_description: Default::default(),
+            gathering_state: Cell::new(RTCIceGatheringState::New),
+            ice_connection_state: Cell::new(RTCIceConnectionState::New),
+            signaling_state: Cell::new(RTCSignalingState::Stable),
+            data_channels: DomRefCell::new(HashMap::new()),
+        }
+    }
+
+    fn new(
+        window: &Window,
+        proto: Option<HandleObject>,
+        config: &RTCConfiguration,
+        can_gc: CanGc,
+    ) -> DomRoot<RTCPeerConnection> {
+        let this = reflect_dom_object_with_proto(
+            Box::new(RTCPeerConnection::new_inherited()),
+            window,
+            proto,
+            can_gc,
+        );
+        let signaller = this.make_signaller();
+        *this.controller.borrow_mut() = Some(ServoMedia::get().create_webrtc(signaller));
+        if let Some(ref servers) = config.iceServers {
+            if let Some(server) = servers.first() {
+                let server = match server.urls {
+                    StringOrStringSequence::String(ref s) => Some(s.clone()),
+                    StringOrStringSequence::StringSequence(ref s) => s.first().cloned(),
+                };
+                if let Some(server) = server {
+                    let policy = match config.bundlePolicy {
+                        RTCBundlePolicy::Balanced => BundlePolicy::Balanced,
+                        RTCBundlePolicy::Max_compat => BundlePolicy::MaxCompat,
+                        RTCBundlePolicy::Max_bundle => BundlePolicy::MaxBundle,
+                    };
+                    this.controller
+                        .borrow()
+                        .as_ref()
+                        .unwrap()
+                        .configure(server.to_string(), policy);
+                }
+            }
+        }
+        this
+    }
+
+    pub(crate) fn get_webrtc_controller(&self) -> &DomRefCell<Option<WebRtcController>> {
+        &self.controller
+    }
+
+    fn make_signaller(&self) -> Box<dyn WebRtcSignaller> {
+        let trusted = Trusted::new(self);
+        Box::new(RTCSignaller {
+            trusted,
+            task_source: self.global().task_manager().networking_task_source().into(),
+        })
+    }
+
+    fn on_ice_candidate(&self, candidate: IceCandidate, can_gc: CanGc) {
+        if self.closed.get() {
+            return;
+        }
+        let candidate = RTCIceCandidate::new(
+            self.global().as_window(),
+            candidate.candidate.into(),
+            None,
+            Some(candidate.sdp_mline_index as u16),
+            None,
+            can_gc,
+        );
+        let event = RTCPeerConnectionIceEvent::new(
+            self.global().as_window(),
+            atom!("icecandidate"),
+            Some(&candidate),
+            None,
+            true,
+            can_gc,
+        );
+        event.upcast::<Event>().fire(self.upcast(), can_gc);
+    }
+
+    fn on_negotiation_needed(&self, can_gc: CanGc) {
+        if self.closed.get() {
+            return;
+        }
+        let event = Event::new(
+            &self.global(),
+            atom!("negotiationneeded"),
+            EventBubbles::DoesNotBubble,
+            EventCancelable::NotCancelable,
+            can_gc,
+        );
+        event.upcast::<Event>().fire(self.upcast(), can_gc);
+    }
+
+    fn on_add_stream(&self, id: MediaStreamId, ty: MediaStreamType, can_gc: CanGc) {
+        if self.closed.get() {
+            return;
+        }
+        let track = MediaStreamTrack::new(&self.global(), id, ty, can_gc);
+        let event = RTCTrackEvent::new(
+            self.global().as_window(),
+            atom!("track"),
+            false,
+            false,
+            &track,
+            can_gc,
+        );
+        event.upcast::<Event>().fire(self.upcast(), can_gc);
+    }
+
+    fn on_data_channel_event(
+        &self,
+        channel_id: DataChannelId,
+        event: DataChannelEvent,
+        can_gc: CanGc,
+    ) {
+        if self.closed.get() {
+            return;
+        }
+
+        match event {
+            DataChannelEvent::NewChannel => {
+                let channel = RTCDataChannel::new(
+                    &self.global(),
+                    self,
+                    USVString::from("".to_owned()),
+                    &RTCDataChannelInit::empty(),
+                    Some(channel_id),
+                    can_gc,
+                );
+
+                let event = RTCDataChannelEvent::new(
+                    self.global().as_window(),
+                    atom!("datachannel"),
+                    false,
+                    false,
+                    &channel,
+                    can_gc,
+                );
+                event.upcast::<Event>().fire(self.upcast(), can_gc);
+            },
+            _ => {
+                let channel: DomRoot<RTCDataChannel> =
+                    if let Some(channel) = self.data_channels.borrow().get(&channel_id) {
+                        DomRoot::from_ref(&**channel)
+                    } else {
+                        warn!(
+                            "Got an event for an unregistered data channel {:?}",
+                            channel_id
+                        );
+                        return;
+                    };
+
+                match event {
+                    DataChannelEvent::Open => channel.on_open(can_gc),
+                    DataChannelEvent::Close => channel.on_close(can_gc),
+                    DataChannelEvent::Error(error) => channel.on_error(error, can_gc),
+                    DataChannelEvent::OnMessage(message) => channel.on_message(message, can_gc),
+                    DataChannelEvent::StateChange(state) => channel.on_state_change(state, can_gc),
+                    DataChannelEvent::NewChannel => unreachable!(),
+                }
+            },
+        };
+    }
+
+    pub(crate) fn register_data_channel(&self, id: DataChannelId, channel: &RTCDataChannel) {
+        if self
+            .data_channels
+            .borrow_mut()
+            .insert(id, Dom::from_ref(channel))
+            .is_some()
+        {
+            warn!("Data channel already registered {:?}", id);
+        }
+    }
+
+    pub(crate) fn unregister_data_channel(&self, id: &DataChannelId) {
+        self.data_channels.borrow_mut().remove(id);
+    }
+
+    /// <https://www.w3.org/TR/webrtc/#update-ice-gathering-state>
+    fn update_gathering_state(&self, state: GatheringState, can_gc: CanGc) {
+        // step 1
+        if self.closed.get() {
+            return;
+        }
+
+        // step 2 (state derivation already done by gstreamer)
+        let state: RTCIceGatheringState = state.convert();
+
+        // step 3
+        if state == self.gathering_state.get() {
+            return;
+        }
+
+        // step 4
+        self.gathering_state.set(state);
+
+        // step 5
+        let event = Event::new(
+            &self.global(),
+            atom!("icegatheringstatechange"),
+            EventBubbles::DoesNotBubble,
+            EventCancelable::NotCancelable,
+            can_gc,
+        );
+        event.upcast::<Event>().fire(self.upcast(), can_gc);
+
+        // step 6
+        if state == RTCIceGatheringState::Complete {
+            let event = RTCPeerConnectionIceEvent::new(
+                self.global().as_window(),
+                atom!("icecandidate"),
+                None,
+                None,
+                true,
+                can_gc,
+            );
+            event.upcast::<Event>().fire(self.upcast(), can_gc);
+        }
+    }
+
+    /// <https://www.w3.org/TR/webrtc/#update-ice-connection-state>
+    fn update_ice_connection_state(&self, state: IceConnectionState, can_gc: CanGc) {
+        // step 1
+        if self.closed.get() {
+            return;
+        }
+
+        // step 2 (state derivation already done by gstreamer)
+        let state: RTCIceConnectionState = state.convert();
+
+        // step 3
+        if state == self.ice_connection_state.get() {
+            return;
+        }
+
+        // step 4
+        self.ice_connection_state.set(state);
+
+        // step 5
+        let event = Event::new(
+            &self.global(),
+            atom!("iceconnectionstatechange"),
+            EventBubbles::DoesNotBubble,
+            EventCancelable::NotCancelable,
+            can_gc,
+        );
+        event.upcast::<Event>().fire(self.upcast(), can_gc);
+    }
+
+    fn update_signaling_state(&self, state: SignalingState, can_gc: CanGc) {
+        if self.closed.get() {
+            return;
+        }
+
+        let state: RTCSignalingState = state.convert();
+
+        if state == self.signaling_state.get() {
+            return;
+        }
+
+        self.signaling_state.set(state);
+
+        let event = Event::new(
+            &self.global(),
+            atom!("signalingstatechange"),
+            EventBubbles::DoesNotBubble,
+            EventCancelable::NotCancelable,
+            can_gc,
+        );
+        event.upcast::<Event>().fire(self.upcast(), can_gc);
+    }
+
+    fn create_offer(&self) {
+        let generation = self.offer_answer_generation.get();
+        let task_source = self
+            .global()
+            .task_manager()
+            .networking_task_source()
+            .to_sendable();
+        let this = Trusted::new(self);
+        self.controller
+            .borrow_mut()
+            .as_ref()
+            .unwrap()
+            .create_offer(Box::new(move |desc: SessionDescription| {
+                task_source.queue(task!(offer_created: move || {
+                    let this = this.root();
+                    if this.offer_answer_generation.get() != generation {
+                        // the state has changed since we last created the offer,
+                        // create a fresh one
+                        this.create_offer();
+                    } else {
+                        let init: RTCSessionDescriptionInit = desc.convert();
+                        for promise in this.offer_promises.borrow_mut().drain(..) {
+                            promise.resolve_native(&init, CanGc::note());
+                        }
+                    }
+                }));
+            }));
+    }
+
+    fn create_answer(&self) {
+        let generation = self.offer_answer_generation.get();
+        let task_source = self
+            .global()
+            .task_manager()
+            .networking_task_source()
+            .to_sendable();
+        let this = Trusted::new(self);
+        self.controller
+            .borrow_mut()
+            .as_ref()
+            .unwrap()
+            .create_answer(Box::new(move |desc: SessionDescription| {
+                task_source.queue(task!(answer_created: move || {
+                    let this = this.root();
+                    if this.offer_answer_generation.get() != generation {
+                        // the state has changed since we last created the offer,
+                        // create a fresh one
+                        this.create_answer();
+                    } else {
+                        let init: RTCSessionDescriptionInit = desc.convert();
+                        for promise in this.answer_promises.borrow_mut().drain(..) {
+                            promise.resolve_native(&init, CanGc::note());
+                        }
+                    }
+                }));
+            }));
+    }
+}
+
+impl RTCPeerConnectionMethods<crate::DomTypeHolder> for RTCPeerConnection {
+    // https://w3c.github.io/webrtc-pc/#dom-peerconnection
+    fn Constructor(
+        window: &Window,
+        proto: Option<HandleObject>,
+        can_gc: CanGc,
+        config: &RTCConfiguration,
+    ) -> Fallible<DomRoot<RTCPeerConnection>> {
+        Ok(RTCPeerConnection::new(window, proto, config, can_gc))
+    }
+
+    // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-icecandidate
+    event_handler!(icecandidate, GetOnicecandidate, SetOnicecandidate);
+
+    // https://www.w3.org/TR/webrtc/#dom-rtcpeerconnection-ontrack
+    event_handler!(track, GetOntrack, SetOntrack);
+
+    // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-iceconnectionstatechange
+    event_handler!(
+        iceconnectionstatechange,
+        GetOniceconnectionstatechange,
+        SetOniceconnectionstatechange
+    );
+
+    // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-icegatheringstatechange
+    event_handler!(
+        icegatheringstatechange,
+        GetOnicegatheringstatechange,
+        SetOnicegatheringstatechange
+    );
+
+    // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-onnegotiationneeded
+    event_handler!(
+        negotiationneeded,
+        GetOnnegotiationneeded,
+        SetOnnegotiationneeded
+    );
+
+    // https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-signalingstatechange
+    event_handler!(
+        signalingstatechange,
+        GetOnsignalingstatechange,
+        SetOnsignalingstatechange
+    );
+
+    // https://www.w3.org/TR/webrtc/#dom-rtcpeerconnection-ondatachannel
+    event_handler!(datachannel, GetOndatachannel, SetOndatachannel);
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-addicecandidate>
+    fn AddIceCandidate(
+        &self,
+        candidate: &RTCIceCandidateInit,
+        comp: InRealm,
+        can_gc: CanGc,
+    ) -> Rc<Promise> {
+        let p = Promise::new_in_current_realm(comp, can_gc);
+        if candidate.sdpMid.is_none() && candidate.sdpMLineIndex.is_none() {
+            p.reject_error(
+                Error::Type("one of sdpMid and sdpMLineIndex must be set".to_string()),
+                can_gc,
+            );
+            return p;
+        }
+
+        // XXXManishearth add support for sdpMid
+        if candidate.sdpMLineIndex.is_none() {
+            p.reject_error(
+                Error::Type("servo only supports sdpMLineIndex right now".to_string()),
+                can_gc,
+            );
+            return p;
+        }
+
+        // XXXManishearth this should be enqueued
+        // https://w3c.github.io/webrtc-pc/#enqueue-an-operation
+
+        self.controller
+            .borrow_mut()
+            .as_ref()
+            .unwrap()
+            .add_ice_candidate(IceCandidate {
+                sdp_mline_index: candidate.sdpMLineIndex.unwrap() as u32,
+                candidate: candidate.candidate.to_string(),
+            });
+
+        // XXXManishearth add_ice_candidate should have a callback
+        p.resolve_native(&(), can_gc);
+        p
+    }
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-createoffer>
+    fn CreateOffer(&self, _options: &RTCOfferOptions, comp: InRealm, can_gc: CanGc) -> Rc<Promise> {
+        let p = Promise::new_in_current_realm(comp, can_gc);
+        if self.closed.get() {
+            p.reject_error(Error::InvalidState, can_gc);
+            return p;
+        }
+        self.offer_promises.borrow_mut().push(p.clone());
+        self.create_offer();
+        p
+    }
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-createoffer>
+    fn CreateAnswer(
+        &self,
+        _options: &RTCAnswerOptions,
+        comp: InRealm,
+        can_gc: CanGc,
+    ) -> Rc<Promise> {
+        let p = Promise::new_in_current_realm(comp, can_gc);
+        if self.closed.get() {
+            p.reject_error(Error::InvalidState, can_gc);
+            return p;
+        }
+        self.answer_promises.borrow_mut().push(p.clone());
+        self.create_answer();
+        p
+    }
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-localdescription>
+    fn GetLocalDescription(&self) -> Option<DomRoot<RTCSessionDescription>> {
+        self.local_description.get()
+    }
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-remotedescription>
+    fn GetRemoteDescription(&self) -> Option<DomRoot<RTCSessionDescription>> {
+        self.remote_description.get()
+    }
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-setlocaldescription>
+    fn SetLocalDescription(
+        &self,
+        desc: &RTCSessionDescriptionInit,
+        comp: InRealm,
+        can_gc: CanGc,
+    ) -> Rc<Promise> {
+        // XXXManishearth validate the current state
+        let p = Promise::new_in_current_realm(comp, can_gc);
+        let this = Trusted::new(self);
+        let desc: SessionDescription = desc.convert();
+        let trusted_promise = TrustedPromise::new(p.clone());
+        let task_source = self
+            .global()
+            .task_manager()
+            .networking_task_source()
+            .to_sendable();
+        self.controller
+            .borrow_mut()
+            .as_ref()
+            .unwrap()
+            .set_local_description(
+                desc.clone(),
+                Box::new(move || {
+                    task_source.queue(task!(local_description_set: move || {
+                        // XXXManishearth spec actually asks for an intricate
+                        // dance between pending/current local/remote descriptions
+                        let this = this.root();
+                        let desc = desc.convert();
+                        let desc = RTCSessionDescription::Constructor(
+                            this.global().as_window(),
+                            None,
+                            CanGc::note(),
+                            &desc,
+                        ).unwrap();
+                        this.local_description.set(Some(&desc));
+                        trusted_promise.root().resolve_native(&(), CanGc::note())
+                    }));
+                }),
+            );
+        p
+    }
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-setremotedescription>
+    fn SetRemoteDescription(
+        &self,
+        desc: &RTCSessionDescriptionInit,
+        comp: InRealm,
+        can_gc: CanGc,
+    ) -> Rc<Promise> {
+        // XXXManishearth validate the current state
+        let p = Promise::new_in_current_realm(comp, can_gc);
+        let this = Trusted::new(self);
+        let desc: SessionDescription = desc.convert();
+        let trusted_promise = TrustedPromise::new(p.clone());
+        let task_source = self
+            .global()
+            .task_manager()
+            .networking_task_source()
+            .to_sendable();
+        self.controller
+            .borrow_mut()
+            .as_ref()
+            .unwrap()
+            .set_remote_description(
+                desc.clone(),
+                Box::new(move || {
+                    task_source.queue(task!(remote_description_set: move || {
+                        // XXXManishearth spec actually asks for an intricate
+                        // dance between pending/current local/remote descriptions
+                        let this = this.root();
+                        let desc = desc.convert();
+                        let desc = RTCSessionDescription::Constructor(
+                            this.global().as_window(),
+                            None,
+                            CanGc::note(),
+                            &desc,
+                        ).unwrap();
+                        this.remote_description.set(Some(&desc));
+                        trusted_promise.root().resolve_native(&(), CanGc::note())
+                    }));
+                }),
+            );
+        p
+    }
+
+    // https://w3c.github.io/webrtc-pc/#legacy-interface-extensions
+    fn AddStream(&self, stream: &MediaStream) {
+        for track in &*stream.get_tracks() {
+            self.controller
+                .borrow()
+                .as_ref()
+                .unwrap()
+                .add_stream(&track.id());
+        }
+    }
+
+    /// <https://www.w3.org/TR/webrtc/#dom-rtcpeerconnection-icegatheringstate>
+    fn IceGatheringState(&self) -> RTCIceGatheringState {
+        self.gathering_state.get()
+    }
+
+    /// <https://www.w3.org/TR/webrtc/#dom-rtcpeerconnection-iceconnectionstate>
+    fn IceConnectionState(&self) -> RTCIceConnectionState {
+        self.ice_connection_state.get()
+    }
+
+    /// <https://www.w3.org/TR/webrtc/#dom-rtcpeerconnection-signalingstate>
+    fn SignalingState(&self) -> RTCSignalingState {
+        self.signaling_state.get()
+    }
+
+    /// <https://www.w3.org/TR/webrtc/#dom-rtcpeerconnection-close>
+    fn Close(&self, can_gc: CanGc) {
+        // Step 1
+        if self.closed.get() {
+            return;
+        }
+        // Step 2
+        self.closed.set(true);
+
+        // Step 4
+        self.signaling_state.set(RTCSignalingState::Closed);
+
+        // Step 5 handled by backend
+        self.controller.borrow_mut().as_ref().unwrap().quit();
+
+        // Step 6
+        for (_, val) in self.data_channels.borrow().iter() {
+            val.on_state_change(DataChannelState::Closed, can_gc);
+        }
+
+        // Step 7-10
+        // (no current support for transports, etc)
+
+        // Step 11
+        self.ice_connection_state.set(RTCIceConnectionState::Closed);
+
+        // Step 11
+        // (no current support for connection state)
+    }
+
+    /// <https://www.w3.org/TR/webrtc/#dom-peerconnection-createdatachannel>
+    fn CreateDataChannel(
+        &self,
+        label: USVString,
+        init: &RTCDataChannelInit,
+    ) -> DomRoot<RTCDataChannel> {
+        RTCDataChannel::new(&self.global(), self, label, init, None, CanGc::note())
+    }
+
+    /// <https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-addtransceiver>
+    fn AddTransceiver(
+        &self,
+        _track_or_kind: MediaStreamTrackOrString,
+        init: &RTCRtpTransceiverInit,
+    ) -> DomRoot<RTCRtpTransceiver> {
+        RTCRtpTransceiver::new(&self.global(), init.direction, CanGc::note())
+    }
+}
+
+impl Convert<RTCSessionDescriptionInit> for SessionDescription {
+    fn convert(self) -> RTCSessionDescriptionInit {
+        let type_ = match self.type_ {
+            SdpType::Answer => RTCSdpType::Answer,
+            SdpType::Offer => RTCSdpType::Offer,
+            SdpType::Pranswer => RTCSdpType::Pranswer,
+            SdpType::Rollback => RTCSdpType::Rollback,
+        };
+        RTCSessionDescriptionInit {
+            type_,
+            sdp: self.sdp.into(),
+        }
+    }
+}
+
+impl Convert<SessionDescription> for &RTCSessionDescriptionInit {
+    fn convert(self) -> SessionDescription {
+        let type_ = match self.type_ {
+            RTCSdpType::Answer => SdpType::Answer,
+            RTCSdpType::Offer => SdpType::Offer,
+            RTCSdpType::Pranswer => SdpType::Pranswer,
+            RTCSdpType::Rollback => SdpType::Rollback,
+        };
+        SessionDescription {
+            type_,
+            sdp: self.sdp.to_string(),
+        }
+    }
+}
+
+impl Convert<RTCIceGatheringState> for GatheringState {
+    fn convert(self) -> RTCIceGatheringState {
+        match self {
+            GatheringState::New => RTCIceGatheringState::New,
+            GatheringState::Gathering => RTCIceGatheringState::Gathering,
+            GatheringState::Complete => RTCIceGatheringState::Complete,
+        }
+    }
+}
+
+impl Convert<RTCIceConnectionState> for IceConnectionState {
+    fn convert(self) -> RTCIceConnectionState {
+        match self {
+            IceConnectionState::New => RTCIceConnectionState::New,
+            IceConnectionState::Checking => RTCIceConnectionState::Checking,
+            IceConnectionState::Connected => RTCIceConnectionState::Connected,
+            IceConnectionState::Completed => RTCIceConnectionState::Completed,
+            IceConnectionState::Disconnected => RTCIceConnectionState::Disconnected,
+            IceConnectionState::Failed => RTCIceConnectionState::Failed,
+            IceConnectionState::Closed => RTCIceConnectionState::Closed,
+        }
+    }
+}
+
+impl Convert<RTCSignalingState> for SignalingState {
+    fn convert(self) -> RTCSignalingState {
+        match self {
+            SignalingState::Stable => RTCSignalingState::Stable,
+            SignalingState::HaveLocalOffer => RTCSignalingState::Have_local_offer,
+            SignalingState::HaveRemoteOffer => RTCSignalingState::Have_remote_offer,
+            SignalingState::HaveLocalPranswer => RTCSignalingState::Have_local_pranswer,
+            SignalingState::HaveRemotePranswer => RTCSignalingState::Have_remote_pranswer,
+            SignalingState::Closed => RTCSignalingState::Closed,
+        }
+    }
+}