--- a/dom/animation/DocumentTimeline.cpp
+++ b/dom/animation/DocumentTimeline.cpp
@@ -41,30 +41,29 @@ NS_IMPL_RELEASE_INHERITED(DocumentTimeli
 JSObject*
 DocumentTimeline::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 {
   return DocumentTimelineBinding::Wrap(aCx, this, aGivenProto);
 }
 
 /* static */ already_AddRefed<DocumentTimeline>
 DocumentTimeline::Constructor(const GlobalObject& aGlobal,
-                              const DOMHighResTimeStamp& aOriginTime,
+                              const DocumentTimelineOptions& aOptions,
                               ErrorResult& aRv)
 {
   nsIDocument* doc = AnimationUtils::GetCurrentRealmDocument(aGlobal.Context());
   if (!doc) {
     aRv.Throw(NS_ERROR_FAILURE);
     return nullptr;
   }
+  TimeDuration originTime =
+    TimeDuration::FromMilliseconds(aOptions.mOriginTime);
 
-  TimeDuration originTime = TimeDuration::FromMilliseconds(aOriginTime);
   if (originTime == TimeDuration::Forever() ||
       originTime == -TimeDuration::Forever()) {
-    nsAutoString inputOriginTime;
-    inputOriginTime.AppendFloat(aOriginTime);
     aRv.ThrowTypeError<dom::MSG_TIME_VALUE_OUT_OF_RANGE>(
       NS_LITERAL_STRING("Origin time"));
     return nullptr;
   }
   RefPtr<DocumentTimeline> timeline = new DocumentTimeline(doc, originTime);
 
   return timeline.forget();
 }

--- a/dom/animation/DocumentTimeline.h
+++ b/dom/animation/DocumentTimeline.h
@@ -2,16 +2,17 @@
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* 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/. */
 
 #ifndef mozilla_dom_DocumentTimeline_h
 #define mozilla_dom_DocumentTimeline_h
 
+#include "mozilla/dom/DocumentTimelineBinding.h"
 #include "mozilla/TimeStamp.h"
 #include "AnimationTimeline.h"
 #include "nsIDocument.h"
 #include "nsDOMNavigationTiming.h" // for DOMHighResTimeStamp
 #include "nsRefreshDriver.h"
 
 struct JSContext;
 
@@ -49,17 +50,17 @@ public:
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(DocumentTimeline,
                                                          AnimationTimeline)
 
   virtual JSObject* WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto) override;
 
   static already_AddRefed<DocumentTimeline>
   Constructor(const GlobalObject& aGlobal,
-              const DOMHighResTimeStamp& aOriginTime,
+              const DocumentTimelineOptions& aOptions,
               ErrorResult& aRv);
 
   // AnimationTimeline methods
   virtual Nullable<TimeDuration> GetCurrentTime() const override;
 
   bool TracksWallclockTime() const override
   {
     nsRefreshDriver* refreshDriver = GetRefreshDriver();

--- a/dom/animation/test/mozilla/file_document-timeline-origin-time-range.html
+++ b/dom/animation/test/mozilla/file_document-timeline-origin-time-range.html
@@ -7,20 +7,24 @@
 
 // If the originTime parameter passed to the DocumentTimeline exceeds
 // the range of the internal storage type (a signed 64-bit integer number
 // of ticks--a platform-dependent unit) then we should throw.
 // Infinity isn't allowed as an origin time value and clamping to just
 // inside the allowed range will just mean we overflow elsewhere.
 
 test(function(t) {
-  assert_throws({name: 'TypeError'},
-    function() { new DocumentTimeline(Number.MAX_SAFE_INTEGER); });
+  assert_throws({ name: 'TypeError'},
+    function() {
+      new DocumentTimeline({ originTime: Number.MAX_SAFE_INTEGER });
+    });
 }, 'Calculated current time is positive infinity');
 
 test(function(t) {
-  assert_throws({name: 'TypeError'},
-    function() { new DocumentTimeline(-1 * Number.MAX_SAFE_INTEGER); });
+  assert_throws({ name: 'TypeError'},
+    function() {
+      new DocumentTimeline({ originTime: -1 * Number.MAX_SAFE_INTEGER });
+    });
 }, 'Calculated current time is negative infinity');
 
 done();
 </script>
 </body>

--- a/dom/webidl/DocumentTimeline.webidl
+++ b/dom/webidl/DocumentTimeline.webidl
@@ -5,12 +5,16 @@
  *
  * The origin of this IDL file is
  * https://w3c.github.io/web-animations/#documenttimeline
  *
  * Copyright © 2015 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
+dictionary DocumentTimelineOptions {
+  DOMHighResTimeStamp originTime = 0;
+};
+
 [Func="nsDocument::IsWebAnimationsEnabled",
- Constructor (DOMHighResTimeStamp originTime)]
+ Constructor (optional DocumentTimelineOptions options)]
 interface DocumentTimeline : AnimationTimeline {
 };

deleted file mode 100644
--- a/testing/web-platform/meta/web-animations/interfaces/DocumentTimeline/constructor.html.ini
+++ /dev/null
@@ -1,17 +0,0 @@
-[constructor.html]
-  type: testharness
-  [An origin time of zero is used when none is supplied]
-    expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1302038
-
-  [A zero origin time produces a document timeline with a current time identical to the default document timeline]
-    expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1302038
-
-  [A positive origin time makes the document timeline's current time lag behind the default document timeline]
-    expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1302038
-
-  [A negative origin time makes the document timeline's current time run ahead of the default document timeline]
-    expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1302038

--- a/testing/web-platform/tests/web-animations/interfaces/AnimationTimeline/idlharness.html
+++ b/testing/web-platform/tests/web-animations/interfaces/AnimationTimeline/idlharness.html
@@ -7,17 +7,20 @@
 <script src="/resources/idlharness.js"></script>
 <div id="log"></div>
 <script type="text/plain" id="AnimationTimeline-IDL">
 interface AnimationTimeline {
   readonly attribute double? currentTime;
 };
 </script>
 <script type="text/plain" id="DocumentTimeline-IDL">
-[Constructor (DOMHighResTimeStamp originTime)]
+dictionary DocumentTimelineOptions {
+  DOMHighResTimeStamp originTime = 0;
+};
+[Constructor (optional DocumentTimelineOptions options)]
 interface DocumentTimeline : AnimationTimeline {
 };
 </script>
 <script>
 'use strict';
 
 var idlArray;
 test(function() {