diff --git a/dom/media/PeerConnection.js b/dom/media/PeerConnection.js
index 5655a792c967..dd6029f67d25 100644
--- a/dom/media/PeerConnection.js
+++ b/dom/media/PeerConnection.js
@@ -341,6 +341,10 @@ function RTCPeerConnection() {
 
   this._localType = null;
   this._remoteType = null;
+  // http://rtcweb-wg.github.io/jsep/#rfc.section.4.1.9
+  // canTrickle == null means unknown; when a remote description is received it
+  // is set to true or false based on the presence of the "trickle" ice-option
+  this._canTrickle = null;
 
   // States
   this._iceGatheringState = this._iceConnectionState = "new";
@@ -919,7 +923,7 @@ RTCPeerConnection.prototype = {
             this._onSetRemoteDescriptionSuccess = resolve;
             this._onSetRemoteDescriptionFailure = reject;
             this._impl.setRemoteDescription(type, desc.sdp);
-          }));
+          })).then(() => { this._updateCanTrickle(); });
 
         if (desc.type === "rollback") {
           return setRem;
@@ -947,9 +951,37 @@ RTCPeerConnection.prototype = {
     );
   },
 
-  updateIce: function(config) {
-    throw new this._win.DOMException("updateIce not yet implemented",
-                                     "NotSupportedError");
+  get canTrickleIceCandidates() {
+    return this._canTrickle;
+  },
+
+  _updateCanTrickle: function() {
+    let containsTrickle = section => {
+      let lines = section.toLowerCase().split(/(?:\r\n?|\n)/);
+      return lines.some(line => {
+        let prefix = "a=ice-options:";
+        if (line.substring(0, prefix.length) !== prefix) {
+          return false;
+        }
+        let tokens = line.substring(prefix.length).split(" ");
+        return tokens.some(x => x === "trickle");
+      });
+    };
+
+    let desc = null;
+    try {
+      // The getter for remoteDescription can throw if the pc is closed.
+      desc = this.remoteDescription;
+    } catch (e) {}
+    if (!desc) {
+      this._canTrickle = null;
+      return;
+    }
+
+    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) {
diff --git a/dom/media/tests/mochitest/nonTrickleIce.js b/dom/media/tests/mochitest/nonTrickleIce.js
index ce59b89b54c6..2733b64947b3 100644
--- a/dom/media/tests/mochitest/nonTrickleIce.js
+++ b/dom/media/tests/mochitest/nonTrickleIce.js
@@ -2,6 +2,11 @@
  * 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/. */
 
+function removeTrickleOption(desc) {
+  var sdp = desc.sdp.replace(/\r\na=ice-options:trickle\r\n/, "\r\n");
+  return new mozRTCSessionDescription({ type: desc.type, sdp: sdp });
+}
+
 function makeOffererNonTrickle(chain) {
   chain.replace('PC_LOCAL_SETUP_ICE_HANDLER', [
     function PC_LOCAL_SETUP_NOTRICKLE_ICE_HANDLER(test) {
@@ -14,7 +19,7 @@ function makeOffererNonTrickle(chain) {
   chain.replace('PC_REMOTE_GET_OFFER', [
     function PC_REMOTE_GET_FULL_OFFER(test) {
       return test.pcLocal.endOfTrickleIce.then(() => {
-        test._local_offer = test.pcLocal.localDescription;
+        test._local_offer = removeTrickleOption(test.pcLocal.localDescription);
         test._offer_constraints = test.pcLocal.constraints;
         test._offer_options = test.pcLocal.offerOptions;
       });
@@ -24,11 +29,14 @@ function makeOffererNonTrickle(chain) {
     function PC_REMOTE_REQUIRE_REMOTE_SDP_CANDIDATES(test) {
       info("test.pcLocal.localDescription.sdp: " + JSON.stringify(test.pcLocal.localDescription.sdp));
       info("test._local_offer.sdp" + JSON.stringify(test._local_offer.sdp));
+      is(test.pcRemote._pc.canTrickleIceCandidates, false,
+         "Remote thinks that trickle isn't supported");
       ok(!test.localRequiresTrickleIce, "Local does NOT require trickle");
       ok(test._local_offer.sdp.includes("a=candidate"), "offer has ICE candidates")
       ok(test._local_offer.sdp.includes("a=end-of-candidates"), "offer has end-of-candidates");
     }
   ]);
+  chain.remove('PC_REMOTE_CHECK_CAN_TRICKLE_SYNC');
 }
 
 function makeAnswererNonTrickle(chain) {
@@ -43,7 +51,7 @@ function makeAnswererNonTrickle(chain) {
   chain.replace('PC_LOCAL_GET_ANSWER', [
     function PC_LOCAL_GET_FULL_ANSWER(test) {
       return test.pcRemote.endOfTrickleIce.then(() => {
-        test._remote_answer = test.pcRemote.localDescription;
+        test._remote_answer = removeTrickleOption(test.pcRemote.localDescription);
         test._answer_constraints = test.pcRemote.constraints;
       });
     }
@@ -52,9 +60,12 @@ function makeAnswererNonTrickle(chain) {
     function PC_LOCAL_REQUIRE_REMOTE_SDP_CANDIDATES(test) {
       info("test.pcRemote.localDescription.sdp: " + JSON.stringify(test.pcRemote.localDescription.sdp));
       info("test._remote_answer.sdp" + JSON.stringify(test._remote_answer.sdp));
+      is(test.pcLocal._pc.canTrickleIceCandidates, false,
+         "Local thinks that trickle isn't supported");
       ok(!test.remoteRequiresTrickleIce, "Remote does NOT require trickle");
       ok(test._remote_answer.sdp.includes("a=candidate"), "answer has ICE candidates")
       ok(test._remote_answer.sdp.includes("a=end-of-candidates"), "answer has end-of-candidates");
     }
   ]);
+  chain.remove('PC_LOCAL_CHECK_CAN_TRICKLE_SYNC');
 }
diff --git a/dom/media/tests/mochitest/templates.js b/dom/media/tests/mochitest/templates.js
index 5b9d1377d343..670bf3ee951a 100644
--- a/dom/media/tests/mochitest/templates.js
+++ b/dom/media/tests/mochitest/templates.js
@@ -193,6 +193,15 @@ var commandsPeerConnectionInitial = [
        "Initial remote ICE connection state is 'new'");
   },
 
+  function PC_LOCAL_CHECK_INITIAL_CAN_TRICKLE_SYNC(test) {
+    is(test.pcLocal._pc.canTrickleIceCandidates, null,
+       "Local trickle status should start out unknown");
+  },
+
+  function PC_REMOTE_CHECK_INITIAL_CAN_TRICKLE_SYNC(test) {
+    is(test.pcRemote._pc.canTrickleIceCandidates, null,
+       "Remote trickle status should start out unknown");
+  },
 ];
 
 var commandsGetUserMedia = [
@@ -305,6 +314,11 @@ var commandsPeerConnectionOfferAnswer = [
       });
   },
 
+  function PC_REMOTE_CHECK_CAN_TRICKLE_SYNC(test) {
+    is(test.pcRemote._pc.canTrickleIceCandidates, true,
+       "Remote thinks that local can trickle");
+  },
+
   function PC_LOCAL_SANE_LOCAL_SDP(test) {
     test.pcLocal.localRequiresTrickleIce =
       sdputils.verifySdp(test._local_offer, "offer",
@@ -376,6 +390,11 @@ var commandsPeerConnectionOfferAnswer = [
                          test.testOptions);
   },
 
+  function PC_LOCAL_CHECK_CAN_TRICKLE_SYNC(test) {
+    is(test.pcLocal._pc.canTrickleIceCandidates, true,
+       "Local thinks that remote can trickle");
+  },
+
   function PC_LOCAL_WAIT_FOR_ICE_CONNECTED(test) {
     return waitForIceConnected(test, test.pcLocal);
   },
diff --git a/dom/media/tests/mochitest/test_peerConnection_remoteRollback.html b/dom/media/tests/mochitest/test_peerConnection_remoteRollback.html
index 091a28de93c1..0254ebc656fb 100644
--- a/dom/media/tests/mochitest/test_peerConnection_remoteRollback.html
+++ b/dom/media/tests/mochitest/test_peerConnection_remoteRollback.html
@@ -6,41 +6,45 @@
 <body>
 <pre id="test">
 <script type="application/javascript">
-  createHTML({
-    bug: "952145",
-    title: "Rollback remote offer"
-  });
+createHTML({
+  bug: "952145",
+  title: "Rollback remote offer"
+});
 
-  var test;
-  runNetworkTest(function (options) {
-    test = new PeerConnectionTest(options);
-    test.setMediaConstraints([{audio: true}], [{audio: true}]);
-    test.chain.removeAfter('PC_REMOTE_SET_REMOTE_DESCRIPTION');
-    test.chain.append([
-        function PC_REMOTE_ROLLBACK(test) {
-          return test.setRemoteDescription(
-              test.pcRemote,
-              new RTCSessionDescription({ type: "rollback" }),
-              STABLE);
-        },
+var test;
+runNetworkTest(function (options) {
+  test = new PeerConnectionTest(options);
+  test.setMediaConstraints([{audio: true}], [{audio: true}]);
+  test.chain.removeAfter('PC_REMOTE_CHECK_CAN_TRICKLE_SYNC');
+  test.chain.append([
+    function PC_REMOTE_ROLLBACK(test) {
+      return test.setRemoteDescription(
+        test.pcRemote,
+        new RTCSessionDescription({ type: "rollback" }),
+        STABLE);
+    },
 
-        function PC_LOCAL_ROLLBACK(test) {
-          return test.setLocalDescription(
-              test.pcLocal,
-              new RTCSessionDescription({ type: "rollback", sdp: ""}),
-              STABLE);
-        },
+    function PC_REMOTE_CHECK_CAN_TRICKLE_REVERT_SYNC(test) {
+      is(test.pcRemote._pc.canTrickleIceCandidates, null,
+         "Remote canTrickleIceCandidates is reverted to null");
+    },
 
-        // Rolling back should shut down gathering
-        function PC_LOCAL_WAIT_FOR_END_OF_TRICKLE(test) {
-          return test.pcLocal.endOfTrickleIce;
-        },
-    ]);
-    test.chain.append(commandsPeerConnectionOfferAnswer);
-    test.run();
-  });
+    function PC_LOCAL_ROLLBACK(test) {
+      return test.setLocalDescription(
+        test.pcLocal,
+        new RTCSessionDescription({ type: "rollback", sdp: "" }),
+        STABLE);
+    },
+
+    // Rolling back should shut down gathering
+    function PC_LOCAL_WAIT_FOR_END_OF_TRICKLE(test) {
+      return test.pcLocal.endOfTrickleIce;
+    },
+  ]);
+  test.chain.append(commandsPeerConnectionOfferAnswer);
+  test.run();
+});
 </script>
 </pre>
 </body>
 </html>
-
diff --git a/dom/webidl/RTCPeerConnection.webidl b/dom/webidl/RTCPeerConnection.webidl
index 923b38a215d2..1fbd01c801c1 100644
--- a/dom/webidl/RTCPeerConnection.webidl
+++ b/dom/webidl/RTCPeerConnection.webidl
@@ -4,7 +4,7 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * The origin of this IDL file is
- * http://dev.w3.org/2011/webrtc/editor/webrtc.html#idl-def-RTCPeerConnection
+ * http://w3c.github.io/webrtc-pc/#interface-definition
  */
 
 callback RTCSessionDescriptionCallback = void (RTCSessionDescription sdp);
@@ -103,8 +103,8 @@ interface RTCPeerConnection : EventTarget  {
   readonly attribute RTCSessionDescription? localDescription;
   readonly attribute RTCSessionDescription? remoteDescription;
   readonly attribute RTCSignalingState signalingState;
-  void updateIce (optional RTCConfiguration configuration);
   Promise<void> addIceCandidate (RTCIceCandidate candidate);
+  readonly attribute boolean? canTrickleIceCandidates;
   readonly attribute RTCIceGatheringState iceGatheringState;
   readonly attribute RTCIceConnectionState iceConnectionState;
   [Pref="media.peerconnection.identity.enabled"]
diff --git a/testing/web-platform/meta/webrtc/rtcpeerconnection/rtcpeerconnection-idl.html.ini b/testing/web-platform/meta/webrtc/rtcpeerconnection/rtcpeerconnection-idl.html.ini
index d9bfc0c33735..c4d43682899b 100644
--- a/testing/web-platform/meta/webrtc/rtcpeerconnection/rtcpeerconnection-idl.html.ini
+++ b/testing/web-platform/meta/webrtc/rtcpeerconnection/rtcpeerconnection-idl.html.ini
@@ -13,7 +13,7 @@
     expected: FAIL
 
   [RTCPeerConnection interface: attribute canTrickleIceCandidates]
-    expected: FAIL
+    expected: PASS
 
   [RTCPeerConnection interface: attribute onicegatheringstatechange]
     expected: FAIL
@@ -109,7 +109,7 @@
     expected: FAIL
 
   [RTCPeerConnection interface: pc must inherit property "canTrickleIceCandidates" with the proper type (14)]
-    expected: FAIL
+    expected: PASS
 
   [RTCPeerConnection interface: pc must inherit property "setConfiguration" with the proper type (16)]
     expected: FAIL
@@ -172,7 +172,7 @@
     expected: FAIL
 
   [RTCPeerConnection interface: attribute canTrickleIceCandidates]
-    expected: FAIL
+    expected: PASS
 
   [RTCPeerConnection interface: attribute onicegatheringstatechange]
     expected: FAIL
@@ -244,7 +244,7 @@
     expected: FAIL
 
   [RTCPeerConnection interface: pc must inherit property "canTrickleIceCandidates" with the proper type (11)]
-    expected: FAIL
+    expected: PASS
 
   [RTCPeerConnection interface: pc must inherit property "onnegotiationneeded" with the proper type (14)]
     expected: FAIL