--- a/dom/events/test/test_all_synthetic_events.html
+++ b/dom/events/test/test_all_synthetic_events.html
@@ -97,16 +97,20 @@ const kEventConstructors = {
                                              },
   CompositionEvent:                          { create: function (aName, aProps) {
                                                          var e = document.createEvent("compositionevent");
                                                          e.initCompositionEvent(aName, aProps.bubbles, aProps.cancelable,
                                                                                 aProps.view, aProps.data, aProps.locale);
                                                          return e;
                                                        },
                                              },
+  CSSFontFaceLoadEvent:                      { create: function (aName, aProps) {
+                                                         return new CSSFontFaceLoadEvent(aName, aProps);
+                                                       },
+                                             },
   CustomEvent:                               { create: function (aName, aProps) {
                                                          return new CustomEvent(aName, aProps);
                                                        },
                                              },
   DataErrorEvent:                            { create: function (aName, aProps) {
                                                           return new DataErrorEvent(aName, aProps);
                                                        },
                                              },

--- a/dom/tests/mochitest/general/test_interfaces.html
+++ b/dom/tests/mochitest/general/test_interfaces.html
@@ -250,16 +250,18 @@ var interfaceNamesInGlobalScope =
     "CSS2Properties",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSCharsetRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSConditionRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSCounterStyleRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
+    {name: "CSSFontFaceLoadEvent", pref: "layout.css.font-loading-api.enabled"},
+// IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSFontFaceRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSFontFeatureValuesRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSGroupingRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSImportRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
@@ -394,16 +396,20 @@ var interfaceNamesInGlobalScope =
     "FileReader",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "FMRadio", b2g: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "FocusEvent",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "FormData",
 // IMPORTANT: Do not change this list without review from a DOM peer!
+    {name: "FontFace", pref: "layout.css.font-loading-api.enabled"},
+// IMPORTANT: Do not change this list without review from a DOM peer!
+    {name: "FontFaceSet", pref: "layout.css.font-loading-api.enabled"},
+// IMPORTANT: Do not change this list without review from a DOM peer!
     "GainNode",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "Gamepad", b2g: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "GamepadAxisMoveEvent", b2g: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "GamepadButtonEvent", b2g: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!

new file mode 100644
--- /dev/null
+++ b/dom/webidl/CSSFontFaceLoadEvent.webidl
@@ -0,0 +1,21 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/.
+ *
+ * The origin of this IDL file is
+ * http://dev.w3.org/csswg/css-font-loading/#FontFaceSet-interface
+ *
+ * Copyright © 2014 W3C® (MIT, ERCIM, Keio, Beihang), All Rights Reserved. W3C
+ * liability, trademark and document use rules apply.
+ */
+
+dictionary CSSFontFaceLoadEventInit : EventInit {
+  sequence<FontFace> fontfaces = [];
+};
+
+[Constructor(DOMString type, optional CSSFontFaceLoadEventInit eventInitDict),
+ Pref="layout.css.font-loading-api.enabled"]
+interface CSSFontFaceLoadEvent : Event {
+  [Cached, Constant] readonly attribute sequence<FontFace> fontfaces;
+};

--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -356,8 +356,9 @@ partial interface Document {
 };
 
 Document implements XPathEvaluator;
 Document implements GlobalEventHandlers;
 Document implements TouchEventHandlers;
 Document implements ParentNode;
 Document implements OnErrorEventHandlerForNodes;
 Document implements GeometryUtils;
+Document implements FontFaceSource;

new file mode 100644
--- /dev/null
+++ b/dom/webidl/FontFace.webidl
@@ -0,0 +1,46 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/.
+ *
+ * The origin of this IDL file is
+ * http://dev.w3.org/csswg/css-font-loading/#fontface-interface
+ *
+ * Copyright © 2014 W3C® (MIT, ERCIM, Keio, Beihang), All Rights Reserved. W3C
+ * liability, trademark and document use rules apply.
+ */
+
+typedef (ArrayBuffer or ArrayBufferView) BinaryData;
+
+dictionary FontFaceDescriptors {
+  DOMString style = "normal";
+  DOMString weight = "normal";
+  DOMString stretch = "normal";
+  DOMString unicodeRange = "U+0-10FFFF";
+  DOMString variant = "normal";
+  DOMString featureSettings = "normal";
+};
+
+enum FontFaceLoadStatus { "unloaded", "loading", "loaded", "error" };
+
+// Bug 1072107 is for exposing this in workers.
+// [Exposed=(Window,Worker)]
+[Constructor(DOMString family,
+             (DOMString or BinaryData) source,
+             optional FontFaceDescriptors descriptors),
+ Pref="layout.css.font-loading-api.enabled"]
+interface FontFace {
+  [SetterThrows] attribute DOMString family;
+  [SetterThrows] attribute DOMString style;
+  [SetterThrows] attribute DOMString weight;
+  [SetterThrows] attribute DOMString stretch;
+  [SetterThrows] attribute DOMString unicodeRange;
+  [SetterThrows] attribute DOMString variant;
+  [SetterThrows] attribute DOMString featureSettings;
+
+  readonly attribute FontFaceLoadStatus status;
+
+  Promise<FontFace> load();
+
+  readonly attribute Promise<FontFace> loaded;
+};

new file mode 100644
--- /dev/null
+++ b/dom/webidl/FontFaceSet.webidl
@@ -0,0 +1,63 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/.
+ *
+ * The origin of this IDL file is
+ * http://dev.w3.org/csswg/css-font-loading/#FontFaceSet-interface
+ *
+ * Copyright © 2014 W3C® (MIT, ERCIM, Keio, Beihang), All Rights Reserved. W3C
+ * liability, trademark and document use rules apply.
+ */
+
+enum FontFaceSetLoadStatus { "loading", "loaded" };
+
+// Bug 1072762 is for the FontFaceSet constructor.
+// [Constructor(sequence<FontFace> initialFaces)]
+[Pref="layout.css.font-loading-api.enabled"]
+interface FontFaceSet : EventTarget {
+
+  // Emulate the Set interface, until we can extend Set correctly.
+  // Implementing these commented out operations and the iterator is
+  // bug 1072101.
+  // readonly attribute unsigned long size;
+  [Throws] void add(FontFace font);
+  boolean has(FontFace font);
+  [Throws] boolean delete(FontFace font);
+  void clear();
+  // Iterator entries();
+  // Iterator keys();
+  // Iterator values();
+  // void forEach(ForEachCallback cb, optional any thisArg);
+  // FontFace iterator;
+
+  // -- events for when loading state changes
+  attribute EventHandler onloading;
+  attribute EventHandler onloadingdone;
+  attribute EventHandler onloadingerror;
+
+  // check and start loads if appropriate
+  // and fulfill promise when all loads complete
+  // Not implemented yet: bug 1072102.
+  [Throws] Promise<sequence<FontFace>> load(DOMString font, optional DOMString text = " ");
+
+  // return whether all fonts in the fontlist are loaded
+  // (does not initiate load if not available)
+  // Not implemented yet: bug 1072102.
+  // [Throws] boolean check(DOMString font, optional DOMString text = " ");
+
+  // async notification that font loading and layout operations are done
+  [Throws] readonly attribute Promise<void> ready;
+
+  // loading state, "loading" while one or more fonts loading, "loaded" otherwise
+  readonly attribute FontFaceSetLoadStatus status;
+};
+
+// This provides access to the FontFace objects in the FontFaceSet until we
+// get iterators working (bug 1072101).  Don't enable the pref for the CSS Font
+// Loading API until the iterator is available, as we don't want to expose more
+// indexed properties on the Web.
+partial interface FontFaceSet {
+  getter FontFace (unsigned long index);
+  readonly attribute unsigned long length;
+};

new file mode 100644
--- /dev/null
+++ b/dom/webidl/FontFaceSource.webidl
@@ -0,0 +1,18 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/.
+ *
+ * The origin of this IDL file is
+ * http://dev.w3.org/csswg/css-font-loading/#font-face-source
+ *
+ * Copyright © 2014 W3C® (MIT, ERCIM, Keio, Beihang), All Rights Reserved. W3C
+ * liability, trademark and document use rules apply.
+ */
+
+[NoInterfaceObject]
+interface FontFaceSource {
+
+  [Throws, Pref="layout.css.font-loading-api.enabled"]
+  readonly attribute FontFaceSet fonts;
+};

--- a/dom/webidl/WorkerGlobalScope.webidl
+++ b/dom/webidl/WorkerGlobalScope.webidl
@@ -34,16 +34,19 @@ partial interface WorkerGlobalScope {
   void importScripts(DOMString... urls);
 
   readonly attribute WorkerNavigator navigator;
 };
 
 WorkerGlobalScope implements WindowTimers;
 WorkerGlobalScope implements WindowBase64;
 
+// Not implemented yet: bug 1072107.
+// WorkerGlobalScope implements FontFaceSource;
+
 // Mozilla extensions
 partial interface WorkerGlobalScope {
   attribute EventHandler onclose;
 
   void dump(optional DOMString str);
 
   // XXXbz no spec for this yet, because the webperf WG is a bit dysfunctional
   readonly attribute Performance performance;

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -125,16 +125,19 @@ WEBIDL_FILES = [
     'EventSource.webidl',
     'EventTarget.webidl',
     'File.webidl',
     'FileList.webidl',
     'FileMode.webidl',
     'FileReader.webidl',
     'FileReaderSync.webidl',
     'FocusEvent.webidl',
+    'FontFace.webidl',
+    'FontFaceSet.webidl',
+    'FontFaceSource.webidl',
     'FormData.webidl',
     'Function.webidl',
     'GainNode.webidl',
     'Geolocation.webidl',
     'GeometryUtils.webidl',
     'GetUserMediaRequest.webidl',
     'Headers.webidl',
     'History.webidl',
@@ -643,16 +646,17 @@ if CONFIG['MOZ_B2G_FM']:
 
 GENERATED_EVENTS_WEBIDL_FILES = [
     'AutocompleteErrorEvent.webidl',
     'BlobEvent.webidl',
     'CallEvent.webidl',
     'CallGroupErrorEvent.webidl',
     'CFStateChangeEvent.webidl',
     'CloseEvent.webidl',
+    'CSSFontFaceLoadEvent.webidl',
     'DataErrorEvent.webidl',
     'DataStoreChangeEvent.webidl',
     'DeviceLightEvent.webidl',
     'DeviceOrientationEvent.webidl',
     'DeviceProximityEvent.webidl',
     'DeviceStorageChangeEvent.webidl',
     'DOMTransactionEvent.webidl',
     'DownloadEvent.webidl',

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2114,16 +2114,19 @@ pref("layout.css.scroll-behavior.spring-
 // oscillate.
 // When greater than 1.0, the system is over-damped; it will reach the target at
 // reduced speed without overshooting.
 // When equal to 1.0, the system is critically-damped; it will reach the target
 // at the greatest speed without overshooting.
 pref("layout.css.scroll-behavior.damping-ratio", "1.0");
 
 // Is support for document.fonts enabled?
+//
+// Don't enable the pref for the CSS Font Loading API until bug 1072101 is
+// fixed, as we don't want to expose more indexed properties on the Web.
 pref("layout.css.font-loading-api.enabled", false);
 
 // pref for which side vertical scrollbars should be on
 // 0 = end-side in UI direction
 // 1 = end-side in document/content direction
 // 2 = right
 // 3 = left
 pref("layout.scrollbar.side", 0);