diff --git a/dom/events/test/test_eventTimeStamp.html b/dom/events/test/test_eventTimeStamp.html
index 107a21f872..056203e920 100644
--- a/dom/events/test/test_eventTimeStamp.html
+++ b/dom/events/test/test_eventTimeStamp.html
@@ -17,7 +17,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=77992
 <script type="text/js-worker" id="worker-src">
   // Simply returns the event timestamp
   onmessage = function(evt) {
-    postMessage(evt.timeStamp);
+    postMessage(evt.timeStamp + performance.timeOrigin);
   }
 </script>
 <script type="text/js-worker" id="shared-worker-src">
@@ -25,7 +25,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=77992
   onconnect = function(evt) {
     var port = evt.ports[0];
     port.onmessage = function(messageEvt) {
-      port.postMessage(messageEvt.timeStamp);
+      port.postMessage(messageEvt.timeStamp + performance.timeOrigin);
     };
   };
 </script>
@@ -57,9 +57,9 @@ function testRegularEvents() {
     finishTests();
     return;
   }
-  var timeBeforeEvent = window.performance.now();
-  window.addEventListener("load", function(evt) {
-    var timeAfterEvent = window.performance.now();
+  var timeBeforeEvent = performance.now();
+  addEventListener("load", function(evt) {
+    var timeAfterEvent = performance.now();
     ok(evt.timeStamp >= timeBeforeEvent &&
        evt.timeStamp <= timeAfterEvent,
        "Event timestamp (" + evt.timeStamp + ") is in expected range: (" +
@@ -71,19 +71,18 @@ function testRegularEvents() {
 function testWorkerEvents() {
   var blob = new Blob([ document.getElementById("worker-src").textContent ],
                       { type: "text/javascript" });
-  var worker = new Worker(window.URL.createObjectURL(blob));
+  var worker = new Worker(URL.createObjectURL(blob));
   worker.onmessage = function(evt) {
-    var timeAfterEvent = window.performance.now();
-    // Comparing times across timelines may break now
-    // ok(evt.data >= timeBeforeEvent &&
-    //    evt.data <= timeAfterEvent,
+    var timeAfterEvent = performance.now() + performance.timeOrigin;
+    ok(evt.data >= timeBeforeEvent &&
+       evt.data <= timeAfterEvent,
     //   "Event timestamp in dedicated worker (" + evt.data +
     //     ") is in expected range: (" +
     //     timeBeforeEvent + ", " + timeAfterEvent + ")");
     worker.terminate();
     testSharedWorkerEvents();
   };
-  var timeBeforeEvent = window.performance.now();
+  var timeBeforeEvent = performance.now() + performance.timeOrigin;
   worker.postMessage("");
 }
 
@@ -93,17 +92,16 @@ function testSharedWorkerEvents() {
              { type: "text/javascript" });
   // Delay creation of worker slightly so it is easier to distinguish
   // shared worker creation time from this document's navigation start
-  window.setTimeout(function() {
-    var timeBeforeWorkerCreation = window.performance.now();
-    var worker = new SharedWorker(window.URL.createObjectURL(blob));
+  setTimeout(function() {
+  var timeBeforeEvent = performance.now() + performance.timeOrigin;
+    var worker = new SharedWorker(URL.createObjectURL(blob));
     worker.port.onmessage = function(evt) {
-      var timeAfterEvent = window.performance.now();
-      // Comparing times across timelines may break now
-      // ok(evt.data >= 0 &&
-      //   evt.data <= timeAfterEvent - timeBeforeWorkerCreation,
+      var timeAfterEvent = performance.now() + performance.timeOrigin;
+      ok(evt.data >= timeBeforeEvent &&
+         evt.data <= timeAfterEvent,
       //   "Event timestamp in shared worker (" + evt.data +
       //     ") is in expected range: (0, " +
-      //     (timeAfterEvent - timeBeforeWorkerCreation) + ")");
+      //     timeBeforeEvent + ", " + timeAfterEvent + ")");
       worker.port.close();
       finishTests();
     };
diff --git a/dom/performance/tests/mochitest.ini b/dom/performance/tests/mochitest.ini
index 7005637e1b..bee0b2e700 100644
--- a/dom/performance/tests/mochitest.ini
+++ b/dom/performance/tests/mochitest.ini
@@ -13,3 +13,4 @@ support-files =
 [test_worker_observer.html]
 [test_sharedWorker_performance_user_timing.html]
 [test_worker_performance_now.html]
+[test_timeOrigin.html]
diff --git a/dom/performance/tests/test_timeOrigin.html b/dom/performance/tests/test_timeOrigin.html
new file mode 100644
index 0000000000..5a8a461f30
--- /dev/null
+++ b/dom/performance/tests/test_timeOrigin.html
@@ -0,0 +1,68 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <title>Test for performance.timeOrigin</title>
+    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
+    <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="text/javascript" src="test_performance_user_timing.js"></script>
+  </head>
+  <body>
+    <script type="text/js-worker" id="worker-src">
+      postMessage({ now: performance.now(), timeOrigin: performance.timeOrigin });
+    </script>
+
+    <script type="text/js-worker" id="shared-worker-src">
+      onconnect = function(evt) {
+        evt.ports[0].postMessage({ now: performance.now(), timeOrigin: performance.timeOrigin });
+      };
+    </script>
+
+    <script class="testbody" type="text/javascript">
+
+function testBasic() {
+  ok("timeOrigin" in performance, "Performance.timeOrigin exists.");
+  ok(performance.timeOrigin > 0, "TimeOrigin must be greater than 0.");
+  next();
+}
+
+function testWorker() {
+  var now = performance.now();
+
+  var blob = new Blob([ document.getElementById("worker-src").textContent ],
+                      { type: "text/javascript" });
+  var w = new Worker(URL.createObjectURL(blob));
+  w.onmessage = function(e) {
+    ok (e.now + e.timeOrigin > now + performance.now, "Comparing worker.now and window.now");
+    next();
+  }
+}
+
+function testSharedWorker() {
+  var now = performance.now();
+
+  var blob = new Blob([ document.getElementById("shared-worker-src").textContent ],
+                      { type: "text/javascript" });
+  var w = new SharedWorker(URL.createObjectURL(blob));
+  w.port.onmessage = function(e) {
+    ok (e.now + e.timeOrigin > now + performance.now, "Comparing worker.now and window.now");
+    next();
+  }
+}
+
+var tests = [ testBasic, testWorker, testSharedWorker ];
+function next() {
+  if (!tests.length) {
+    SimpleTest.finish();
+    return;
+  }
+
+  var test = tests.shift();
+  test();
+}
+
+SimpleTest.waitForExplicitFinish();
+addLoadEvent(next);
+      </script>
+    </pre>
+  </body>
+</html>