--- a/dom/camera/test/camera_common.js
+++ b/dom/camera/test/camera_common.js
@@ -80,17 +80,17 @@ function CameraTestSuite() {
   this.rejectTakePicture = this._rejectTakePicture.bind(this);
   this.rejectStartRecording = this._rejectStartRecording.bind(this);
   this.rejectStopRecording = this._rejectStopRecording.bind(this);
   this.rejectPreviewStarted = this._rejectPreviewStarted.bind(this);
 
   var self = this;
   this._window.addEventListener('beforeunload', function() {
     if (isDefinedObj(self.viewfinder)) {
-      self.viewfinder.mozSrcObject = null;
+      self.viewfinder.srcObject = null;
     }
 
     self.hw = null;
     if (isDefinedObj(self.camera)) {
       ok(false, 'window unload triggered camera release instead of test completion');
       self.camera.release();
       self.camera = null;
     }
@@ -206,17 +206,17 @@ CameraTestSuite.prototype = {
 
       function resetLowMem() {
         return self.setLowMemoryPlatform(false);
       }
 
       function postTest(pass) {
         ok(pass, test.name + ' finished');
         var camera = self.camera;
-        self.viewfinder.mozSrcObject = null;
+        self.viewfinder.srcObject = null;
         self.camera = null;
 
         if (!isDefinedObj(camera)) {
           return Promise.resolve();
         }
 
         function handler(e) {
           ok(typeof(e) === 'undefined', 'camera released');
@@ -320,17 +320,17 @@ CameraTestSuite.prototype = {
         }
       }
 
       if (!isDefinedObj(self.viewfinder)) {
         reject(new Error('no viewfinder object'));
         return;
       }
 
-      self.viewfinder.mozSrcObject = self.camera;
+      self.viewfinder.srcObject = self.camera;
       self.viewfinder.play();
       self.camera.addEventListener('previewstatechange', onPreviewStateChange);
     });
   },
 
   /* Returns a promise which resolves when the camera hardware
      has received a push parameters request. This is useful
      when setting camera parameters from the application and

--- a/dom/camera/test/test_bug1104913.html
+++ b/dom/camera/test/test_bug1104913.html
@@ -37,17 +37,17 @@ var Camera = {
     return document.getElementById('viewfinder');
   },
 
   start: function test_start() {
     function getCamera_onSuccess(d) {
       var camera = d.camera;
       var cfg = d.configuration;
       Camera.cameraObj = camera;
-      Camera.viewfinder.mozSrcObject = camera;
+      Camera.viewfinder.srcObject = camera;
       Camera.viewfinder.play();
 
       // Check the default configuration
       ok(cfg.mode === config.mode, "Initial mode = " + cfg.mode);
       ok(cfg.previewSize.width === config.previewSize.width &&
          cfg.previewSize.height === config.previewSize.height,
          "Initial preview size = " + cfg.previewSize.width + "x" + cfg.previewSize.height);
       ok(cfg.pictureSize.width === config.pictureSize.width &&
@@ -61,17 +61,17 @@ var Camera = {
 
     navigator.mozCameras.getCamera(whichCamera, {}).then(getCamera_onSuccess, onError);
   }
 }
 
 SimpleTest.waitForExplicitFinish();
 
 window.addEventListener('beforeunload', function() {
-  Camera.viewfinder.mozSrcObject = null;
+  Camera.viewfinder.srcObject = null;
   if (Camera.cameraObj) {
     Camera.cameraObj.release();
     Camera.cameraObj = null;
   }
 });
 
 Camera.start();
 

--- a/dom/camera/test/test_camera.html
+++ b/dom/camera/test/test_camera.html
@@ -227,30 +227,30 @@ var Camera = {
   },
   setUp: function setup_tests() {
     function onSuccess(d) {
       Camera.cameraObj = d.camera;
       Camera.cameraObj.addEventListener('previewstatechange', Camera.onPreviewStateChange);
       Camera.cameraObj.addEventListener('configurationchanged', Camera.onConfigChange);
       Camera.cameraObj.addEventListener('shutter', Camera.shutter);
       Camera.cameraObj.addEventListener('picture', Camera.takePictureEvent.bind(Camera));
-      Camera.viewfinder.mozSrcObject = d.camera;
+      Camera.viewfinder.srcObject = d.camera;
       Camera.viewfinder.play();
       SimpleTest.expectAssertions(0);
       ok(true, "Camera Control object has been successfully initialized");
       Camera.cameraObj.setConfiguration(options).then(Camera.onConfigChange, onError);
     };
     navigator.mozCameras.getCamera(whichCamera, null).then(onSuccess, onError);
   }
 }
 
 SimpleTest.waitForExplicitFinish();
 
 window.addEventListener('beforeunload', function() {
-  Camera.viewfinder.mozSrcObject = null;
+  Camera.viewfinder.srcObject = null;
   Camera.cameraObj.release();
   Camera.cameraObj = null;
 });
 
 Camera.setUp();
 
 </script>
 </body>

--- a/dom/camera/test/test_camera_2.html
+++ b/dom/camera/test/test_camera_2.html
@@ -174,28 +174,28 @@ var Camera = {
       ok(config.mode === options.mode, "configuration mode = " + config.mode);
       ok(config.recorderProfile === options.recorderProfile, "recorder profile = " + config.recorderProfile);
       ok(config.previewSize.width === options.previewSize.width &&
         config.previewSize.height === options.previewSize.height,
         "preview size (w x h) = " + config.previewSize.width + " x " + config.previewSize.height);
       Camera.cameraObj = d.camera;
       Camera.cameraObj.addEventListener('previewstatechange', Camera.onPreviewStateChange);
       Camera.cameraObj.addEventListener('shutter', Camera.shutter);
-      Camera.viewfinder.mozSrcObject = d.camera;
+      Camera.viewfinder.srcObject = d.camera;
       Camera.viewfinder.play();
       SimpleTest.expectAssertions(0);
     };
     navigator.mozCameras.getCamera(whichCamera, options).then(onSuccess, onError);
   }
 }
 
 SimpleTest.waitForExplicitFinish();
 
 window.addEventListener('beforeunload', function() {
-  Camera.viewfinder.mozSrcObject = null;
+  Camera.viewfinder.srcObject = null;
   Camera.cameraObj.release();
   Camera.cameraObj = null;
 });
 
 Camera.setUp();
 
 </script>
 </body>

--- a/dom/camera/test/test_camera_3.html
+++ b/dom/camera/test/test_camera_3.html
@@ -49,27 +49,27 @@ var Camera = {
   },
   release: function release() {
     cameraObj = null;
   },
   start: function run_test() {
     function onSuccess(d) {
       Camera.cameraObj = d.camera;
       Camera.cameraObj.addEventListener('previewstatechange', Camera.onPreviewStateChange);
-      Camera.viewfinder.mozSrcObject = d.camera;
+      Camera.viewfinder.srcObject = d.camera;
       Camera.viewfinder.play();
     };
     navigator.mozCameras.getCamera(whichCamera, options).then(onSuccess, onError);
   }
 }
 
 SimpleTest.waitForExplicitFinish();
 
 window.addEventListener('beforeunload', function() {
-  Camera.viewfinder.mozSrcObject = null;
+  Camera.viewfinder.srcObject = null;
   Camera.cameraObj.release();
   Camera.cameraObj = null;
 });
 
 Camera.start();
 
 </script>
 </body>

--- a/dom/canvas/test/captureStream_common.js
+++ b/dom/canvas/test/captureStream_common.js
@@ -30,17 +30,17 @@ CaptureStreamTestHelper.prototype = {
 
   /* Default element size for createAndAppendElement() */
   elemWidth: 100,
   elemHeight: 100,
 
   /* Request a frame from the stream played by |video|. */
   requestFrame: function (video) {
     info("Requesting frame from " + video.id);
-    video.mozSrcObject.requestFrame();
+    video.srcObject.requestFrame();
   },
 
   /* Tests the top left pixel of |video| against |refData|. Format [R,G,B,A]. */
   testPixel: function (video, refData, threshold) {
     var ctxout = this.cout.getContext('2d');
     ctxout.drawImage(video, 0, 0);
     var pixel = ctxout.getImageData(0, 0, 1, 1).data;
     return pixel.every((val, i) => Math.abs(val - refData[i]) <= threshold);

--- a/dom/canvas/test/reftest/capturestream.html
+++ b/dom/canvas/test/reftest/capturestream.html
@@ -14,17 +14,17 @@ function finished() {
 
 function runTest() {
   var canvas = document.getElementById('canvas');
   var context = canvas.getContext('2d');
   context.fillStyle = "rgba(0, 255, 0, 1)";
   context.fillRect(0, 0, canvas.width, canvas.height);
 
   var video = document.getElementById('video');
-  video.mozSrcObject = canvas.captureStream(0);
+  video.srcObject = canvas.captureStream(0);
   video.play();
   video.onloadeddata = finished;
   video.onerror = finished;
 }
   </script>
 </head>
 
 <body onload='runTest();'>

--- a/dom/canvas/test/reftest/webgl-capturestream-test.html
+++ b/dom/canvas/test/reftest/webgl-capturestream-test.html
@@ -28,17 +28,17 @@ function runTest() {
     setStatus('WebGL context creation failed.');
     return;
   }
 
   gl.clearColor(0.0, 1.0, 0.0, 1.0);
   gl.clear(gl.COLOR_BUFFER_BIT);
 
   var video = document.getElementById('video');
-  video.mozSrcObject = canvas.captureStream(0);
+  video.srcObject = canvas.captureStream(0);
   video.play();
   video.onloadeddata = finished;
   video.onerror = finished;
 }
   </script>
 </head>
 
 <body onload='runTest();'>

--- a/dom/canvas/test/test_capture.html
+++ b/dom/canvas/test/test_capture.html
@@ -14,19 +14,19 @@ var vauto;   // Video element with captu
 var vmanual; // Video element with captureStream stream in manual (fps 0) mode.
 var vrate;   // Video element with captureStream stream with fixed frame rate.
 
 function checkDrawColorInitialRed() {
   info("Checking that all video elements become red after first drawColor(red).");
 
   h.drawColor(c, h.red);
 
-  vauto.mozSrcObject = c.captureStream();
-  vmanual.mozSrcObject = c.captureStream(0);
-  vrate.mozSrcObject = c.captureStream(10);
+  vauto.srcObject = c.captureStream();
+  vmanual.srcObject = c.captureStream(0);
+  vrate.srcObject = c.captureStream(10);
 
   ok(h.testPixel(vauto, [0, 0, 0, 0], 0), "vauto hould not be drawn to before stable state");
   ok(h.testPixel(vrate, [0, 0, 0, 0], 0), "vrate Should not be drawn to before stable state");
   ok(h.testPixel(vmanual, [0, 0, 0, 0], 0), "vmanual Should not be drawn to before stable state");
 
   return Promise.resolve()
     .then(() => h.waitForPixel(vauto, h.red, 0, "should become red automatically"))
     .then(() => h.waitForPixel(vrate, h.red, 0, "should become red automatically"))

--- a/dom/canvas/test/webgl-mochitest/test_capture.html
+++ b/dom/canvas/test/webgl-mochitest/test_capture.html
@@ -45,19 +45,19 @@ function checkGLError(info) {
   is("0x" + error.toString(16), "0x0", "WebGL error [" + info + "]");
 }
 
 function checkClearColorInitialRed() {
   info("Checking that clearing to red works for first frame.");
 
   h.clearColor(c, h.red);
 
-  vauto.mozSrcObject = c.captureStream();
-  vmanual.mozSrcObject = c.captureStream(0);
-  vrate.mozSrcObject = c.captureStream(10);
+  vauto.srcObject = c.captureStream();
+  vmanual.srcObject = c.captureStream(0);
+  vrate.srcObject = c.captureStream(10);
 
   ok(h.testPixel(vauto, [0, 0, 0, 0], 0), "Should not be drawn to before stable state");
   ok(h.testPixel(vrate, [0, 0, 0, 0], 0), "Should not be drawn to before stable state");
   ok(h.testPixel(vmanual, [0, 0, 0, 0], 0), "Should not be drawn to before stable state");
 
   return Promise.resolve()
     .then(() => h.waitForPixel(vauto, h.red, 0, "should become red automatically"))
     .then(() => h.waitForPixel(vrate, h.red, 0, "should become red automatically"))

--- a/dom/media/test/manifest.js
+++ b/dom/media/test/manifest.js
@@ -1333,22 +1333,22 @@ function getMajorMimeType(mimetype) {
   } else {
     return "audio";
   }
 }
 
 // Force releasing decoder to avoid timeout in waiting for decoding resource.
 function removeNodeAndSource(n) {
   n.remove();
-  // Clearing mozSrcObject and/or src will actually set them to some default
+  // Clearing srcObject and/or src will actually set them to some default
   // URI that will fail to load, so make sure we don't produce a spurious
   // bailing error.
   n.onerror = null;
-  // reset |mozSrcObject| first since it takes precedence over |src|.
-  n.mozSrcObject = null;
+  // reset |srcObject| first since it takes precedence over |src|.
+  n.srcObject = null;
   n.src = "";
   while (n.firstChild) {
     n.removeChild(n.firstChild);
   }
 }
 
 function once(target, name, cb) {
   var p = new Promise(function(resolve, reject) {

--- a/dom/media/test/test_bug879717.html
+++ b/dom/media/test/test_bug879717.html
@@ -115,16 +115,16 @@ var startTest = function(media, token) {
   v3.onended = onended;
 
   document.body.appendChild(v1);
   document.body.appendChild(v2);
   document.body.appendChild(v3);
 
   v1.src = media.name;
   v2.src = media.name;
-  v3.mozSrcObject = v2.mozCaptureStreamUntilEnded();
+  v3.srcObject = v2.mozCaptureStreamUntilEnded();
 }
 
 manager.runTests(getPlayableVideos(gSmallTests), startTest);
 </script>
 </pre>
 </body>
 </html>

--- a/dom/media/test/test_mediarecorder_record_4ch_audiocontext.html
+++ b/dom/media/test/test_mediarecorder_record_4ch_audiocontext.html
@@ -26,17 +26,17 @@ function startTest() {
   var stopTriggered = false;
   var onstopTriggered = false;
   dest.channelCount = 4;
   var expectedMimeType = 'audio/ogg';
   var totalBlobSize = 0;
   source.channelCountMode = 'explicit';
   source.connect(dest);
   var elem = document.createElement('audio');
-  elem.mozSrcObject = dest.stream;
+  elem.srcObject = dest.stream;
   mMediaStream = dest.stream;
   source.start(0);
   elem.play();
   mMediaRecorder = new MediaRecorder(dest.stream);
   mMediaRecorder.onwarning = function() {
     ok(false, 'onwarning unexpectedly fired');
   };
 

--- a/dom/media/test/test_mediarecorder_record_audiocontext.html
+++ b/dom/media/test/test_mediarecorder_record_audiocontext.html
@@ -20,17 +20,17 @@ function startTest() {
 
   var source = context.createBufferSource();
   source.buffer = buffer;
   source.loop = true;
 
   var dest = context.createMediaStreamDestination();
   source.connect(dest);
   var elem = document.createElement('audio');
-  elem.mozSrcObject = dest.stream;
+  elem.srcObject = dest.stream;
   mMediaStream = dest.stream;
   source.start(0);
   elem.play();
   mMediaRecorder = new MediaRecorder(dest.stream);
   mMediaRecorder.onwarning = function() {
     ok(false, 'onwarning unexpectedly fired');
   };
 

--- a/dom/media/test/test_mediatrack_consuming_mediastream.html
+++ b/dom/media/test/test_mediatrack_consuming_mediastream.html
@@ -123,17 +123,17 @@ function startTest() {
           checkTrackChanged(1, false);
         } else if (steps == 3) {
           checkTrackChanged(2, true);
           stream.stop();
         }
       }
 
       var steps = 0;
-      element.mozSrcObject = stream;
+      element.srcObject = stream;
       element.onplaying = onplaying;
       element.onended = onended;
       element.play();
       steps++;
     },
     function(err) {
       ok(false, 'Unexpected error fired with: ' + err);
       SimpleTest.finish();

--- a/dom/media/test/test_multiple_mediastreamtracks.html
+++ b/dom/media/test/test_multiple_mediastreamtracks.html
@@ -16,17 +16,17 @@ function startTest() {
 
     element.onloadedmetadata = function() {
       is(stream.getAudioTracks().length, 4, 'Length of audio tracks should be 4.');
       is(stream.getVideoTracks().length, 3, 'Length of vudio tracks should be 3.');
       SimpleTest.finish();
     };
 
     mStream = stream;
-    element.mozSrcObject = mStream;
+    element.srcObject = mStream;
     element.play();
   })
   .catch(function(reason) {
     ok(false, "unexpected error = " + reason.message);
     SimpleTest.finish();
   });
 }
 

--- a/dom/media/test/test_streams_autoplay.html
+++ b/dom/media/test/test_streams_autoplay.html
@@ -15,17 +15,17 @@ SimpleTest.waitForExplicitFinish();
 
 var media = getPlayableVideo(gSmallTests);
 
 if (media == null) {
   todo(false, "No media supported.");
   SimpleTest.finish();
 } else {
   v1.src = media.name;
-  v2.mozSrcObject = v1.mozCaptureStream();
+  v2.srcObject = v1.mozCaptureStream();
   var onPlayingEventFired = false;
 
   v2.onplaying = function() {
     if(!onPlayingEventFired) {
       onPlayingEventFired = true;
       ok(true, "playback started");
       SimpleTest.finish();
     }

--- a/dom/media/test/test_streams_element_capture.html
+++ b/dom/media/test/test_streams_element_capture.html
@@ -33,18 +33,18 @@ function startTest(test, token) {
   var vout = document.createElement('video');
   vout.token = token;
   v.name = token + "(v)";
   vout.name = token + "(vout)";
 
   v.src = test.name;
   var stream = v.mozCaptureStreamUntilEnded();
   is(stream.currentTime, 0, test.name + " stream initial currentTime");
-  vout.mozSrcObject = stream;
-  is(vout.mozSrcObject, stream, test.name + " set output element .srcObject correctly");
+  vout.srcObject = stream;
+  is(vout.srcObject, stream, test.name + " set output element .srcObject correctly");
 
   var checkEnded = function(test, vout, stream) { return function() {
     is(stream.currentTime, vout.currentTime, test.name + " stream final currentTime");
     if (test.duration) {
       ok(Math.abs(vout.currentTime - test.duration) < 0.1,
          test.name + " current time at end: " + vout.currentTime + " should be: " + test.duration);
     }
     is(vout.readyState, vout.HAVE_CURRENT_DATA, test.name + " checking readyState");

--- a/dom/media/test/test_streams_element_capture_reset.html
+++ b/dom/media/test/test_streams_element_capture_reset.html
@@ -12,18 +12,18 @@
 <video id="vout_untilended"></video>
 <pre id="test">
 <script class="testbody" type="text/javascript">
 SimpleTest.waitForExplicitFinish();
 
 var v = document.getElementById('v');
 var vout = document.getElementById('vout');
 var vout_untilended = document.getElementById('vout_untilended');
-vout.mozSrcObject = v.mozCaptureStream();
-vout_untilended.mozSrcObject = v.mozCaptureStreamUntilEnded();
+vout.srcObject = v.mozCaptureStream();
+vout_untilended.srcObject = v.mozCaptureStreamUntilEnded();
 
 function dumpEvent(event) {
   var v = event.target;
   info(v.name + " GOT EVENT " + event.type +
        " currentTime=" + v.currentTime +
        " paused=" + v.paused +
        " ended=" + v.ended +
        " readyState=" + v.readyState);

--- a/dom/media/test/test_streams_srcObject.html
+++ b/dom/media/test/test_streams_srcObject.html
@@ -1,54 +1,62 @@
 <!DOCTYPE HTML>
 <html>
 <head>
   <title>Test interactions of src and srcObject</title>
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
   <script type="text/javascript" src="manifest.js"></script>
 </head>
-<body onload="doTest()">
-<audio id="a"></audio>
+<body onload="doTests()">
+<audio id="a1"></audio>
+<audio id="a2"></audio>
 <pre id="test">
 <script class="testbody" type="text/javascript">
 SimpleTest.waitForExplicitFinish();
 
-var a = document.getElementById('a');
-a.src = getPlayableAudio(gSmallTests).name;
+var doTest = srcObject => new Promise(resolve => {
+  var a = document.getElementById('a1');
+  a.src = getPlayableAudio(gSmallTests).name;
+  var b = new Audio();
 
-var b = new Audio();
-
-function doTest() {
   var newSrc = a.src + "?2";
   b.src = newSrc;
-  is(b.mozSrcObject, null, "Initial srcObject is null");
+  is(b[srcObject], null, "Initial srcObject is null");
   var stream = a.mozCaptureStream();
-  b.mozSrcObject = stream;
-  is(b.mozSrcObject, stream, "Stream set correctly");
+  b[srcObject] = stream;
+  is(b[srcObject], stream, "Stream set correctly");
   try {
-    b.mozSrcObject = "invalid";
-    ok(false, "Setting mozSrcObject to an invalid value should throw.");
+    b[srcObject] = "invalid";
+    ok(false, "Setting srcObject to an invalid value should throw.");
   } catch (e) {
     ok(e instanceof TypeError, "Exception should be a TypeError");
   }
-  is(b.mozSrcObject, stream, "Stream not set to invalid value");
+  is(b[srcObject], stream, "Stream not set to invalid value");
   is(b.src, newSrc, "src attribute not affected by setting srcObject");
   var step = 0;
   b.addEventListener("loadedmetadata", function() {
     if (step == 0) {
       is(b.currentSrc, "", "currentSrc set to empty string while playing srcObject");
-      b.mozSrcObject = null;
-      is(b.mozSrcObject, null, "Stream set to null");
+      b[srcObject] = null;
+      is(b[srcObject], null, "Stream set to null");
       // The resource selection algorithm will run again and choose b.src
     } else if (step == 1) {
       is(b.currentSrc, b.src, "currentSrc set to src now that srcObject is null");
-      SimpleTest.finish();
+      resolve();
     }
     ++step;
   });
   a.play();
   b.play();
-}
+});
+
+// TODO: remove prefixed version soon (1183495).
+
+var doTests = () => doTest("srcObject").then(() => doTest("mozSrcObject"))
+  .catch(e => ok(false, "Unexpected error: " + e))
+  .then(() => SimpleTest.finish())
+  .catch(e => ok(false, "Coding error: " + e));
+
 </script>
 </pre>
 </body>
 </html>

--- a/dom/media/tests/mochitest/blacksilence.js
+++ b/dom/media/tests/mochitest/blacksilence.js
@@ -60,17 +60,17 @@
         silence = false;
       }
     }
     return silence;
   }
 
   function checkAudio(constraintApplied, stream) {
     var audio = mkElement('audio');
-    audio.mozSrcObject = stream;
+    audio.srcObject = stream;
     audio.play();
 
     var context = new AudioContext();
     var source = context.createMediaStreamSource(stream);
     var analyser = context.createAnalyser();
     source.connect(analyser);
     analyser.connect(context.destination);
 
@@ -88,17 +88,17 @@
       analyser.disconnect();
       audio.pause();
       ok(true, 'audio is ' + (constraintApplied ? '' : 'not ') + 'silent');
     });
   }
 
   function checkVideo(constraintApplied, stream) {
     var video = mkElement('video');
-    video.mozSrcObject = stream;
+    video.srcObject = stream;
     video.play();
 
     return periodicCheck(() => {
       try {
         var canvas = mkElement('canvas');
         var ctx = canvas.getContext('2d');
         // Have to guard drawImage with the try as well, due to bug 879717. If
         // we get an error, this round fails, but that failure is usually just

--- a/dom/media/tests/mochitest/mediaStreamPlayback.js
+++ b/dom/media/tests/mochitest/mediaStreamPlayback.js
@@ -117,17 +117,17 @@ MediaStreamPlayback.prototype = {
       };
 
       // Adds a listener intended to be fired when playback is available
       // without further buffering.
       this.mediaElement.addEventListener('canplaythrough', canPlayThroughCallback,
                                          false);
 
       // Hooks up the media stream to the media element and starts playing it
-      this.mediaElement.mozSrcObject = this.mediaStream;
+      this.mediaElement.srcObject = this.mediaStream;
       this.mediaElement.play();
 
       // If canplaythrough doesn't fire in enough time, we fail the test
       setTimeout(() => {
         this.mediaElement.removeEventListener('canplaythrough',
                                               canPlayThroughCallback, false);
         reject(new Error("canplaythrough event never fired"));
       }, CANPLAYTHROUGH_TIMEOUT_LENGTH);
@@ -137,17 +137,17 @@ MediaStreamPlayback.prototype = {
   /**
    * Stops the media with the associated stream.
    *
    * Precondition: The media stream and element should both be actively
    *               being played.
    */
   stopMediaElement : function() {
     this.mediaElement.pause();
-    this.mediaElement.mozSrcObject = null;
+    this.mediaElement.srcObject = null;
   }
 }
 
 
 /**
  * This class is basically the same as MediaStreamPlayback except
  * ensures that the instance provided startMedia is a MediaStream.
  *

--- a/dom/media/tests/mochitest/pc.js
+++ b/dom/media/tests/mochitest/pc.js
@@ -808,17 +808,17 @@ PeerConnectionWrapper.prototype = {
             type: track.kind,
             streamId: stream.id
           };
       });
     }
 
     var element = createMediaElement(type, this.label + '_' + side + this.streams.length);
     this.mediaElements.push(element);
-    element.mozSrcObject = stream;
+    element.srcObject = stream;
     element.play();
 
     // Store local media elements so that we can stop them when done.
     // Don't store remote ones because they should stop when the PC does.
     if (side === 'local') {
       this.localMediaElements.push(element);
       return this.observedNegotiationNeeded;
     }

--- a/dom/media/tests/mochitest/test_getUserMedia_basicVideo_playAfterLoadedmetadata.html
+++ b/dom/media/tests/mochitest/test_getUserMedia_basicVideo_playAfterLoadedmetadata.html
@@ -19,17 +19,17 @@
     var constraints = {video: true};
 
     return getUserMedia(constraints).then(stream => {
       checkMediaStreamTracks(constraints, stream);
 
       var playback = new LocalMediaStreamPlayback(testVideo, stream);
       var video = playback.mediaElement;
 
-      video.mozSrcObject = stream;
+      video.srcObject = stream;
       return new Promise(resolve => {
         ok(playback.mediaElement.paused,
            "Media element should be paused before play()ing");
         video.addEventListener('loadedmetadata', function() {
           ok(video.videoWidth > 0, "Expected nonzero video width");
           ok(video.videoHeight > 0, "Expected nonzero video width");
           resolve();
         });

--- a/dom/media/tests/mochitest/test_peerConnection_promiseSendOnly.html
+++ b/dom/media/tests/mochitest/test_peerConnection_promiseSendOnly.html
@@ -1,9 +1,9 @@
-<!DOCTYPE HTML>
+<!DOCTYPE HTML>
 <html>
 <head>
   <script type="application/javascript" src="pc.js"></script>
 </head>
 <body>
 <pre id="test">
 <script type="application/javascript;version=1.8">
   createHTML({
@@ -22,36 +22,36 @@
 
   pc1.onicecandidate = e => pc2_haveRemoteOffer.then(() => !e.candidate ||
     pc2.addIceCandidate(e.candidate)).catch(generateErrorCallback());
   pc2.onicecandidate = e => pc1_stable.then(() => !e.candidate ||
     pc1.addIceCandidate(e.candidate)).catch(generateErrorCallback());
 
   var v1, v2;
   var delivered = new Promise(resolve =>
-    pc2.onaddstream = e => resolve(v2.mozSrcObject = e.stream));
+    pc2.onaddstream = e => resolve(v2.srcObject = e.stream));
 
   runNetworkTest(function() {
     v1 = createMediaElement('video', 'v1');
     v2 = createMediaElement('video', 'v2');
     var canPlayThrough = new Promise(resolve => v2.canplaythrough = e => resolve());
 
     is(v2.currentTime, 0, "v2.currentTime is zero at outset");
 
     navigator.mediaDevices.getUserMedia({ fake: true, video: true, audio: true })
-    .then(stream => pc1.addStream(v1.mozSrcObject = stream))
+    .then(stream => pc1.addStream(v1.srcObject = stream))
     .then(() => pc1.createOffer({})) // check that createOffer accepts arg.
     .then(offer => pc1.setLocalDescription(offer))
     .then(() => pc2.setRemoteDescription(pc1.localDescription))
     .then(() => pc2.createAnswer({}))  // check that createAnswer accepts arg.
     .then(answer => pc2.setLocalDescription(answer))
     .then(() => pc1.setRemoteDescription(pc2.localDescription))
     .then(() => delivered)
 //    .then(() => canPlayThrough)    // why doesn't this fire?
-    .then(() => waitUntil(() => v2.currentTime > 0 && v2.mozSrcObject.currentTime > 0))
+    .then(() => waitUntil(() => v2.currentTime > 0 && v2.srcObject.currentTime > 0))
     .then(() => ok(v2.currentTime > 0, "v2.currentTime is moving (" + v2.currentTime + ")"))
     .then(() => ok(true, "Connected."))
     .catch(reason => ok(false, "unexpected failure: " + reason))
     .then(networkTestFinished);
   });
 </script>
 </pre>
 </body>

--- a/dom/media/webaudio/test/test_mediaStreamAudioDestinationNode.html
+++ b/dom/media/webaudio/test/test_mediaStreamAudioDestinationNode.html
@@ -22,17 +22,17 @@ addLoadEvent(function() {
 
   var source = context.createBufferSource();
   source.buffer = buffer;
 
   var dest = context.createMediaStreamDestination();
   source.connect(dest);
 
   var elem = document.getElementById('audioelem');
-  elem.mozSrcObject = dest.stream;
+  elem.srcObject = dest.stream;
   elem.onloadedmetadata = function() {
     ok(true, "got metadata event");
     setTimeout(function() {
       is(elem.played.length, 1, "should have a played interval");
       is(elem.played.start(0), 0, "should have played immediately");
       isnot(elem.played.end(0), 0, "should have played for a non-zero interval");
       SimpleTest.finish();
     }, 2000);

--- a/mobile/android/tests/browser/robocop/robocop_getusermedia.html
+++ b/mobile/android/tests/browser/robocop/robocop_getusermedia.html
@@ -30,55 +30,55 @@
       },
       audio: true
     };
     startMedia(mediaConstraints);
   }
 
   function stopMedia() {
     if (video_status) {
-      video.mozSrcObject.stop();
-      video.mozSrcObject = null;
+      video.srcObject.stop();
+      video.srcObject = null;
       content.removeChild(video);
       capturing = false;
       video_status = false;
     }
     if (audio_status) {
-      audio.mozSrcObject.stop();
-      audio.mozSrcObject = null;
+      audio.srcObject.stop();
+      audio.srcObject = null;
       content.removeChild(audio);
       audio_status = false;
     }
   }
 
   function startMedia(param) {
     try {
       window.navigator.mozGetUserMedia(param, function(stream) {
         if (video_status) {
           content.appendChild(video);
-          video.mozSrcObject = stream;
+          video.srcObject = stream;
           video.play();
         }
         if (audio_status) {
           content.appendChild(audio);
-          audio.mozSrcObject = stream;
+          audio.srcObject = stream;
           audio.play();
         }
         var audioTracks = stream.getAudioTracks();
         var videoTracks = stream.getVideoTracks();
         document.title = "";
         if (audioTracks.length > 0) {
           document.title += "audio";
         }
         if (videoTracks.length > 0) {
           document.title += "video";
         }
         document.title += " gumtest";
-        audio.mozSrcObject.stop();
-        video.mozSrcObject.stop();
+        audio.srcObject.stop();
+        video.srcObject.stop();
       }, function(err) {
         document.title = "failed gumtest";
         stopMedia();
       });
     } catch(e) {
       stopMedia();
     }
   }