--- a/dom/media/MediaStreamTrack.cpp
+++ b/dom/media/MediaStreamTrack.cpp
@@ -245,16 +245,26 @@ MediaStreamTrack::Stop()
   DOMMediaStream::TrackPort* port = mOwningStream->FindOwnedTrackPort(*this);
   MOZ_ASSERT(port, "A MediaStreamTrack must exist in its owning DOMMediaStream");
   RefPtr<Pledge<bool>> p = port->BlockSourceTrackId(mInputTrackID, BlockingMode::CREATION);
   Unused << p;
 
   mReadyState = MediaStreamTrackState::Ended;
 }
 
+void MediaStreamTrack::GetConstraints(dom::MediaTrackConstraints& aResult)
+{
+  aResult = mConstraints;
+}
+
+void MediaStreamTrack::GetSettings(dom::MediaTrackSettings& aResult)
+{
+  aResult = mSettings;
+}
+
 already_AddRefed<Promise>
 MediaStreamTrack::ApplyConstraints(const MediaTrackConstraints& aConstraints,
                                    ErrorResult &aRv)
 {
   if (MOZ_LOG_TEST(gMediaStreamTrackLog, LogLevel::Info)) {
     nsString str;
     aConstraints.ToJSON(str);
 

--- a/dom/media/MediaStreamTrack.h
+++ b/dom/media/MediaStreamTrack.h
@@ -9,16 +9,18 @@
 #include "mozilla/DOMEventTargetHelper.h"
 #include "nsError.h"
 #include "nsID.h"
 #include "nsIPrincipal.h"
 #include "StreamTracks.h"
 #include "MediaTrackConstraints.h"
 #include "mozilla/CORSMode.h"
 #include "PrincipalChangeObserver.h"
+#include "mozilla/dom/MediaStreamTrackBinding.h"
+#include "mozilla/dom/MediaTrackSettingsBinding.h"
 
 namespace mozilla {
 
 class DOMMediaStream;
 class MediaEnginePhotoCallback;
 class MediaInputPort;
 class MediaStream;
 class MediaStreamGraph;
@@ -258,16 +260,19 @@ public:
 
   // WebIDL
   virtual void GetKind(nsAString& aKind) = 0;
   void GetId(nsAString& aID) const;
   void GetLabel(nsAString& aLabel) { GetSource().GetLabel(aLabel); }
   bool Enabled() { return mEnabled; }
   void SetEnabled(bool aEnabled);
   void Stop();
+  void GetConstraints(dom::MediaTrackConstraints& aResult);
+  void GetSettings(dom::MediaTrackSettings& aResult);
+
   already_AddRefed<Promise>
   ApplyConstraints(const dom::MediaTrackConstraints& aConstraints, ErrorResult &aRv);
   already_AddRefed<MediaStreamTrack> Clone();
   MediaStreamTrackState ReadyState() { return mReadyState; }
 
   IMPL_EVENT_HANDLER(ended)
 
   /**
@@ -421,14 +426,16 @@ protected:
   // Keep tracking MediaStreamTrackListener and DirectMediaStreamTrackListener,
   // so we can remove them in |Destory|.
   nsTArray<RefPtr<MediaStreamTrackListener>> mTrackListeners;
   nsTArray<RefPtr<DirectMediaStreamTrackListener>> mDirectTrackListeners;
   nsString mID;
   MediaStreamTrackState mReadyState;
   bool mEnabled;
   const bool mRemote;
+  dom::MediaTrackConstraints mConstraints;
+  dom::MediaTrackSettings mSettings;
 };
 
 } // namespace dom
 } // namespace mozilla
 
 #endif /* MEDIASTREAMTRACK_H_ */

--- a/dom/webidl/MediaStreamTrack.webidl
+++ b/dom/webidl/MediaStreamTrack.webidl
@@ -79,15 +79,15 @@ interface MediaStreamTrack : EventTarget
 //              attribute EventHandler          onunmute;
 //  readonly    attribute boolean               _readonly;
 //  readonly    attribute boolean               remote;
     readonly    attribute MediaStreamTrackState readyState;
                 attribute EventHandler          onended;
     MediaStreamTrack       clone ();
     void                   stop ();
 //  MediaTrackCapabilities getCapabilities ();
-//  MediaTrackConstraints  getConstraints ();
-//  MediaTrackSettings     getSettings ();
+    MediaTrackConstraints  getConstraints ();
+    MediaTrackSettings     getSettings ();
 
     [Throws]
     Promise<void>          applyConstraints (optional MediaTrackConstraints constraints);
 //              attribute EventHandler          onoverconstrained;
 };

new file mode 100644
--- /dev/null
+++ b/dom/webidl/MediaTrackSettings.webidl
@@ -0,0 +1,33 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * http://w3c.github.io/mediacapture-main/getusermedia.html
+ */
+
+dictionary MediaTrackSettings {
+    long      width;
+    long      height;
+    double    frameRate;
+    DOMString facingMode;
+    DOMString deviceId;
+
+    // Mozilla-specific extensions:
+
+    // http://fluffy.github.io/w3c-screen-share/#screen-based-video-constraints
+    // OBE by http://w3c.github.io/mediacapture-screen-share
+
+    DOMString mediaSource;
+
+    // Experimental https://bugzilla.mozilla.org/show_bug.cgi?id=1131568#c3
+    //              https://bugzilla.mozilla.org/show_bug.cgi?id=1193075
+
+    long long browserWindow;
+    boolean scrollWithPage;
+    long viewportOffsetX;
+    long viewportOffsetY;
+    long viewportWidth;
+    long viewportHeight;
+};
\ No newline at end of file

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -301,16 +301,17 @@ WEBIDL_FILES = [
     'MediaRecorder.webidl',
     'MediaSource.webidl',
     'MediaStream.webidl',
     'MediaStreamAudioDestinationNode.webidl',
     'MediaStreamAudioSourceNode.webidl',
     'MediaStreamError.webidl',
     'MediaStreamTrack.webidl',
     'MediaTrackConstraintSet.webidl',
+    'MediaTrackSettings.webidl',
     'MediaTrackSupportedConstraints.webidl',
     'MenuBoxObject.webidl',
     'MessageChannel.webidl',
     'MessageEvent.webidl',
     'MessagePort.webidl',
     'MessagePortList.webidl',
     'MimeType.webidl',
     'MimeTypeArray.webidl',