--- a/dom/bindings/test/test_exceptions_from_jsimplemented.html
+++ b/dom/bindings/test/test_exceptions_from_jsimplemented.html
@@ -8,24 +8,24 @@ https://bugzilla.mozilla.org/show_bug.cg
   <title>Test for Bug 923010</title>
   <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
   /** Test for Bug 923010 **/
   try {
     var conn = new RTCPeerConnection();
 
-    var candidate = new RTCIceCandidate({candidate: null });
+    var candidate = new RTCIceCandidate({candidate: "x" });
     conn.addIceCandidate(candidate)
     .then(function() {
       ok(false, "addIceCandidate succeeded when it should have failed");
     }, function(reason) {
       is(reason.lineNumber, 17, "Rejection should have been on line 17");
       is(reason.message,
-         "Invalid candidate passed to addIceCandidate!",
+         "Invalid candidate (both sdpMid and sdpMLineIndex are null).",
          "Should have the rejection we expect");
     })
     .catch(function(reason) {
       ok(false, "unexpected error: " + reason);
     });
   } catch (e) {
     // b2g has no WebRTC, apparently
     todo(false, "No WebRTC on b2g yet");

--- a/dom/media/PeerConnection.js
+++ b/dom/media/PeerConnection.js
@@ -972,22 +972,25 @@ RTCPeerConnection.prototype = {
     }
 
     let sections = desc.sdp.split(/(?:\r\n?|\n)m=/);
     let topSection = sections.shift();
     this._canTrickle =
       containsTrickle(topSection) || sections.every(containsTrickle);
   },
 
-
   addIceCandidate: function(c, onSuccess, onError) {
     return this._legacyCatchAndCloseGuard(onSuccess, onError, () => {
-      if (!c.candidate && !c.sdpMLineIndex) {
-        throw new this._win.DOMException("Invalid candidate passed to addIceCandidate!",
-                                         "InvalidParameterError");
+      if (!c) {
+        // TODO: Implement processing for end-of-candidates (bug 1318167)
+        return Promise.resolve();
+      }
+      if (c.sdpMid === null && c.sdpMLineIndex === null) {
+        throw new this._win.DOMException("Invalid candidate (both sdpMid and sdpMLineIndex are null).",
+                                         "TypeError");
       }
       return this._chain(() => new this._win.Promise((resolve, reject) => {
         this._onAddIceCandidateSuccess = resolve;
         this._onAddIceCandidateError = reject;
         this._impl.addIceCandidate(c.candidate, c.sdpMid || "", c.sdpMLineIndex);
       }));
     });
   },

--- a/dom/media/tests/mochitest/test_peerConnection_addIceCandidate.html
+++ b/dom/media/tests/mochitest/test_peerConnection_addIceCandidate.html
@@ -49,55 +49,58 @@
         return test.pcRemote._pc.addIceCandidate(bogus)
         .then(
           generateErrorCallback("addIceCandidate should have failed."),
           err => {
             is(err.name, "InvalidCandidateError", "Error is InvalidCandidateError");
           }
         );
       },
-      function PC_REMOTE_ADD_CANDIDATE_MISSING_INDEX(test) {
-        // Note: it is probably not a good idea to automatically fill a missing
-        //       MLineIndex with a default value of zero, see bug 1157034
+      function PC_REMOTE_ADD_MISSING_MID_AND_MISSING_INDEX(test) {
         var broken = new RTCIceCandidate(
           {candidate:"candidate:1 1 UDP 2130706431 192.168.2.1 50005 typ host"});
         return test.pcRemote._pc.addIceCandidate(broken)
         .then(
-          // FIXME this needs to be updated once bug 1157034 is fixed
-          todo(false, "Missing index in got automatically set to a valid value bz://1157034")
+          generateErrorCallback("addIceCandidate should have failed."),
+          err => {
+            is(err.name, "TypeError", "Error is TypeError");
+          }
         );
       },
       function PC_REMOTE_ADD_VALID_CANDIDATE(test) {
         var candidate = new RTCIceCandidate(
           {candidate:"candidate:1 1 UDP 2130706431 192.168.2.1 50005 typ host",
            sdpMLineIndex: 0});
         return test.pcRemote._pc.addIceCandidate(candidate)
-        .then(ok(true, "Successfully added valid ICE candidate"));
+        .then(() => ok(true, "Successfully added valid ICE candidate"));
       },
       // bug 1095793
       function PC_REMOTE_ADD_MISMATCHED_MID_AND_LEVEL_CANDIDATE(test) {
         var bogus = new mozRTCIceCandidate(
           {candidate:"candidate:1 1 UDP 2130706431 192.168.2.1 50005 typ host",
            sdpMLineIndex: 0,
            sdpMid: "sdparta_1"});
         return test.pcRemote._pc.addIceCandidate(bogus)
-        .then(
-          generateErrorCallback("addIceCandidate should have failed."),
-          err => {
-            is(err.name, "InvalidCandidateError", "Error is InvalidCandidateError");
-          }
-        );
+        .then(generateErrorCallback("addIceCandidate should have failed."),
+              err => is(err.name, "InvalidCandidateError", "Error is InvalidCandidateError"));
+      },
+      function PC_REMOTE_ADD_MID_AND_MISSING_INDEX(test) {
+        var candidate = new RTCIceCandidate(
+          {candidate:"candidate:1 1 UDP 2130706431 192.168.2.1 50005 typ host",
+           sdpMid: "sdparta_0"});
+        return test.pcRemote._pc.addIceCandidate(candidate)
+        .then(() => ok(true, "Successfully added valid ICE candidate"));
       },
       function PC_REMOTE_ADD_MATCHING_MID_AND_LEVEL_CANDIDATE(test) {
         var candidate = new mozRTCIceCandidate(
           {candidate:"candidate:1 1 UDP 2130706431 192.168.2.1 50005 typ host",
            sdpMLineIndex: 0,
            sdpMid: "sdparta_0"});
         return test.pcRemote._pc.addIceCandidate(candidate)
-        .then(ok(true, "Successfully added valid ICE candidate with matching mid and level"));
+        .then(() => ok(true, "Successfully added valid ICE candidate with matching mid and level"));
       }
     ]);
     test.run();
   });
 </script>
 </pre>
 </body>
 </html>

--- a/dom/webidl/RTCPeerConnection.webidl
+++ b/dom/webidl/RTCPeerConnection.webidl
@@ -84,17 +84,17 @@ interface RTCPeerConnection : EventTarge
   Promise<DOMString> getIdentityAssertion();
   Promise<RTCSessionDescription> createOffer (optional RTCOfferOptions options);
   Promise<RTCSessionDescription> createAnswer (optional RTCAnswerOptions options);
   Promise<void> setLocalDescription (RTCSessionDescription description);
   Promise<void> setRemoteDescription (RTCSessionDescription description);
   readonly attribute RTCSessionDescription? localDescription;
   readonly attribute RTCSessionDescription? remoteDescription;
   readonly attribute RTCSignalingState signalingState;
-  Promise<void> addIceCandidate (RTCIceCandidate candidate);
+  Promise<void> addIceCandidate ((RTCIceCandidateInit or RTCIceCandidate)? candidate);
   readonly attribute boolean? canTrickleIceCandidates;
   readonly attribute RTCIceGatheringState iceGatheringState;
   readonly attribute RTCIceConnectionState iceConnectionState;
   [Pref="media.peerconnection.identity.enabled"]
   readonly attribute Promise<RTCIdentityAssertion> peerIdentity;
   [Pref="media.peerconnection.identity.enabled"]
   readonly attribute DOMString? idpLoginUrl;