summaryrefslogtreecommitdiffstats
path: root/dom/base/CustomElementRegistry.cpp
blob: 2bf969d382d8a3bd4ffebfd59384ea727d2afcf0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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/. */

#include "mozilla/dom/CustomElementRegistry.h"

#include "mozilla/CycleCollectedJSContext.h"
#include "mozilla/dom/CustomElementRegistryBinding.h"
#include "mozilla/dom/HTMLElementBinding.h"
#include "mozilla/dom/WebComponentsBinding.h"
#include "mozilla/dom/DocGroup.h"
#include "mozilla/dom/Promise.h"
#include "nsContentUtils.h"
#include "nsHTMLTags.h"
#include "jsapi.h"

namespace mozilla {
namespace dom {

void
CustomElementCallback::Call()
{
  IgnoredErrorResult rv;
  switch (mType) {
    case nsIDocument::eConnected:
      static_cast<LifecycleConnectedCallback *>(mCallback.get())->Call(mThisObject, rv);
      break;
    case nsIDocument::eDisconnected:
      static_cast<LifecycleDisconnectedCallback *>(mCallback.get())->Call(mThisObject, rv);
      break;
    case nsIDocument::eAdopted:
      static_cast<LifecycleAdoptedCallback *>(mCallback.get())->Call(mThisObject,
        mAdoptedCallbackArgs.mOldDocument, mAdoptedCallbackArgs.mNewDocument, rv);
      break;
    case nsIDocument::eAttributeChanged:
      static_cast<LifecycleAttributeChangedCallback *>(mCallback.get())->Call(mThisObject,
        mArgs.name, mArgs.oldValue, mArgs.newValue, mArgs.namespaceURI, rv);
      break;
  }
}

void
CustomElementCallback::Traverse(nsCycleCollectionTraversalCallback& aCb) const
{
  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(aCb, "mThisObject");
  aCb.NoteXPCOMChild(mThisObject);

  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(aCb, "mCallback");
  aCb.NoteXPCOMChild(mCallback);
}

CustomElementCallback::CustomElementCallback(Element* aThisObject,
                                             nsIDocument::ElementCallbackType aCallbackType,
                                             mozilla::dom::CallbackFunction* aCallback)
  : mThisObject(aThisObject),
    mCallback(aCallback),
    mType(aCallbackType)
{
}

//-----------------------------------------------------
// CustomElementConstructor

already_AddRefed<Element>
CustomElementConstructor::Construct(const char* aExecutionReason,
                                    ErrorResult& aRv)
{
  CallSetup s(this, aRv, aExecutionReason,
              CallbackFunction::eRethrowExceptions);

  JSContext* cx = s.GetContext();
  if (!cx) {
    MOZ_ASSERT(aRv.Failed());
    return nullptr;
  }

  JS::Rooted<JSObject*> result(cx);
  JS::Rooted<JS::Value> constructor(cx, JS::ObjectValue(*mCallback));
  if (!JS::Construct(cx, constructor, JS::HandleValueArray::empty(), &result)) {
    aRv.NoteJSContextException(cx);
    return nullptr;
  }

  RefPtr<Element> element;
  if (NS_FAILED(UNWRAP_OBJECT(Element, &result, element))) {
    return nullptr;
  }

  return element.forget();
}

//-----------------------------------------------------
// CustomElementData

CustomElementData::CustomElementData(nsIAtom* aType)
  : CustomElementData(aType, CustomElementData::State::eUndefined)
{
}

CustomElementData::CustomElementData(nsIAtom* aType, State aState)
  : mState(aState)
  , mType(aType)
{
}

void
CustomElementData::SetCustomElementDefinition(CustomElementDefinition* aDefinition)
{
  MOZ_ASSERT(mState == State::eCustom);
  MOZ_ASSERT(!mCustomElementDefinition);
  MOZ_ASSERT(aDefinition->mType == mType);

  mCustomElementDefinition = aDefinition;
}

CustomElementDefinition*
CustomElementData::GetCustomElementDefinition()
{
  MOZ_ASSERT(mCustomElementDefinition ? mState == State::eCustom
                                      : mState != State::eCustom);

  return mCustomElementDefinition;
}

nsIAtom*
CustomElementData::GetCustomElementType()
{
  return mType;
}

void
CustomElementData::Traverse(nsCycleCollectionTraversalCallback& aCb) const
{
  for (uint32_t i = 0; i < mReactionQueue.Length(); i++) {
    if (mReactionQueue[i]) {
      mReactionQueue[i]->Traverse(aCb);
    }
  }

  if (mCustomElementDefinition) {
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(aCb, "mCustomElementDefinition");
    aCb.NoteNativeChild(mCustomElementDefinition,
      NS_CYCLE_COLLECTION_PARTICIPANT(CustomElementDefinition));
  }
}

void
CustomElementData::Unlink()
{
  mReactionQueue.Clear();
  mCustomElementDefinition = nullptr;
}

//-----------------------------------------------------
// CustomElementRegistry

namespace {

class MOZ_RAII AutoConstructionStackEntry final
{
public:
  AutoConstructionStackEntry(nsTArray<RefPtr<nsGenericHTMLElement>>& aStack,
                             nsGenericHTMLElement* aElement)
    : mStack(aStack)
  {
    mIndex = mStack.Length();
    mStack.AppendElement(aElement);
  }

  ~AutoConstructionStackEntry()
  {
    MOZ_ASSERT(mIndex == mStack.Length() - 1,
               "Removed element should be the last element");
    mStack.RemoveElementAt(mIndex);
  }

private:
  nsTArray<RefPtr<nsGenericHTMLElement>>& mStack;
  uint32_t mIndex;
};

} // namespace anonymous

// Only needed for refcounted objects.
NS_IMPL_CYCLE_COLLECTION_CLASS(CustomElementRegistry)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(CustomElementRegistry)
  tmp->mConstructors.clear();
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mCustomDefinitions)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mWhenDefinedPromiseMap)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mWindow)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CustomElementRegistry)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCustomDefinitions)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWhenDefinedPromiseMap)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWindow)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(CustomElementRegistry)
  for (auto iter = tmp->mCustomDefinitions.Iter(); !iter.Done(); iter.Next()) {
    aCallbacks.Trace(&iter.UserData()->mPrototype,
                     "mCustomDefinitions prototype",
                     aClosure);
  }
  for (ConstructorMap::Enum iter(tmp->mConstructors); !iter.empty(); iter.popFront()) {
    aCallbacks.Trace(&iter.front().mutableKey(),
                     "mConstructors key",
                     aClosure);
  }
  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(CustomElementRegistry)
NS_IMPL_CYCLE_COLLECTING_RELEASE(CustomElementRegistry)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CustomElementRegistry)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

/* static */ bool
CustomElementRegistry::IsCustomElementEnabled(JSContext* aCx, JSObject* aObject)
{
  return nsContentUtils::IsCustomElementsEnabled();
}

CustomElementRegistry::CustomElementRegistry(nsPIDOMWindowInner* aWindow)
 : mWindow(aWindow)
 , mIsCustomDefinitionRunning(false)
{
  MOZ_ASSERT(aWindow);
  MOZ_ASSERT(aWindow->IsInnerWindow());
  MOZ_ALWAYS_TRUE(mConstructors.init());

  mozilla::HoldJSObjects(this);
}

CustomElementRegistry::~CustomElementRegistry()
{
  mozilla::DropJSObjects(this);
}

CustomElementDefinition*
CustomElementRegistry::LookupCustomElementDefinition(nsIAtom* aNameAtom,
                                                     nsIAtom* aTypeAtom) const
{
  CustomElementDefinition* data = mCustomDefinitions.GetWeak(aTypeAtom);
  if (data && data->mLocalName == aNameAtom) {
    return data;
  }

  return nullptr;
}

CustomElementDefinition*
CustomElementRegistry::LookupCustomElementDefinition(JSContext* aCx,
                                                     JSObject* aConstructor) const
{
  JS::Rooted<JSObject*> constructor(aCx, js::CheckedUnwrap(aConstructor));

  const auto& ptr = mConstructors.lookup(constructor);
  if (!ptr) {
    return nullptr;
  }

  CustomElementDefinition* definition = mCustomDefinitions.GetWeak(ptr->value());
  MOZ_ASSERT(definition, "Definition must be found in mCustomDefinitions");

  return definition;
}

void
CustomElementRegistry::RegisterUnresolvedElement(Element* aElement, nsIAtom* aTypeName)
{
  mozilla::dom::NodeInfo* info = aElement->NodeInfo();

  // Candidate may be a custom element through extension,
  // in which case the custom element type name will not
  // match the element tag name. e.g. <button is="x-button">.
  nsCOMPtr<nsIAtom> typeName = aTypeName;
  if (!typeName) {
    typeName = info->NameAtom();
  }

  if (mCustomDefinitions.GetWeak(typeName)) {
    return;
  }

  nsTArray<nsWeakPtr>* unresolved = mCandidatesMap.LookupOrAdd(typeName);
  nsWeakPtr* elem = unresolved->AppendElement();
  *elem = do_GetWeakReference(aElement);

  return;
}

void
CustomElementRegistry::UnregisterUnresolvedElement(Element* aElement,
                                                   nsIAtom* aTypeName)
{
  nsTArray<nsWeakPtr>* candidates;
  if (mCandidatesMap.Get(aTypeName, &candidates)) {
    MOZ_ASSERT(candidates);
    // We don't need to iterate the candidates array and remove the element from
    // the array for performance reason. It'll be handled by bug 1396620.
    for (size_t i = 0; i < candidates->Length(); ++i) {
      nsCOMPtr<Element> elem = do_QueryReferent(candidates->ElementAt(i));
      if (elem && elem.get() == aElement) {
        candidates->RemoveElementAt(i);
      }
    }
  }
}

/* static */ UniquePtr<CustomElementCallback>
CustomElementRegistry::CreateCustomElementCallback(
  nsIDocument::ElementCallbackType aType, Element* aCustomElement,
  LifecycleCallbackArgs* aArgs,
  LifecycleAdoptedCallbackArgs* aAdoptedCallbackArgs,
  CustomElementDefinition* aDefinition)
{
  MOZ_ASSERT(aDefinition, "CustomElementDefinition should not be null");

  MOZ_ASSERT(aCustomElement->GetCustomElementData(),
             "CustomElementData should exist");

  // Let CALLBACK be the callback associated with the key NAME in CALLBACKS.
  CallbackFunction* func = nullptr;
  switch (aType) {
    case nsIDocument::eConnected:
      if (aDefinition->mCallbacks->mConnectedCallback.WasPassed()) {
        func = aDefinition->mCallbacks->mConnectedCallback.Value();
      }
      break;

    case nsIDocument::eDisconnected:
      if (aDefinition->mCallbacks->mDisconnectedCallback.WasPassed()) {
        func = aDefinition->mCallbacks->mDisconnectedCallback.Value();
      }
      break;

    case nsIDocument::eAdopted:
      if (aDefinition->mCallbacks->mAdoptedCallback.WasPassed()) {
        func = aDefinition->mCallbacks->mAdoptedCallback.Value();
      }
      break;

    case nsIDocument::eAttributeChanged:
      if (aDefinition->mCallbacks->mAttributeChangedCallback.WasPassed()) {
        func = aDefinition->mCallbacks->mAttributeChangedCallback.Value();
      }
      break;
  }

  // If there is no such callback, stop.
  if (!func) {
    return nullptr;
  }

  // Add CALLBACK to ELEMENT's callback queue.
  auto callback =
    MakeUnique<CustomElementCallback>(aCustomElement, aType, func);

  if (aArgs) {
    callback->SetArgs(*aArgs);
  }

  if (aAdoptedCallbackArgs) {
    callback->SetAdoptedCallbackArgs(*aAdoptedCallbackArgs);
  }
  return Move(callback);
}

/* static */ void
CustomElementRegistry::EnqueueLifecycleCallback(nsIDocument::ElementCallbackType aType,
                                                Element* aCustomElement,
                                                LifecycleCallbackArgs* aArgs,
                                                LifecycleAdoptedCallbackArgs* aAdoptedCallbackArgs,
                                                CustomElementDefinition* aDefinition)
{
  CustomElementDefinition* definition = aDefinition;
  if (!definition) {
    definition = aCustomElement->GetCustomElementDefinition();
    if (!definition ||
        definition->mLocalName != aCustomElement->NodeInfo()->NameAtom()) {
      return;
    }
  }

  auto callback =
    CreateCustomElementCallback(aType, aCustomElement, aArgs,
                                aAdoptedCallbackArgs, definition);
  if (!callback) {
    return;
  }

  DocGroup* docGroup = aCustomElement->OwnerDoc()->GetDocGroup();
  if (!docGroup) {
    return;
  }

  if (aType == nsIDocument::eAttributeChanged) {
    nsCOMPtr<nsIAtom> attrName = NS_Atomize(aArgs->name);
    if (definition->mObservedAttributes.IsEmpty() ||
        !definition->mObservedAttributes.Contains(attrName)) {
      return;
    }
  }

  CustomElementReactionsStack* reactionsStack =
    docGroup->CustomElementReactionsStack();
  reactionsStack->EnqueueCallbackReaction(aCustomElement, Move(callback));
}

void
CustomElementRegistry::UpgradeCandidates(nsIAtom* aKey,
                                         CustomElementDefinition* aDefinition,
                                         ErrorResult& aRv)
{
  DocGroup* docGroup = mWindow->GetDocGroup();
  if (!docGroup) {
    aRv.Throw(NS_ERROR_UNEXPECTED);
    return;
  }

  // TODO: Bug 1326028 - Upgrade custom element in shadow-including tree order
  nsAutoPtr<nsTArray<nsWeakPtr>> candidates;
  mCandidatesMap.RemoveAndForget(aKey, candidates);
  if (candidates) {
    CustomElementReactionsStack* reactionsStack =
      docGroup->CustomElementReactionsStack();
    for (size_t i = 0; i < candidates->Length(); ++i) {
      nsCOMPtr<Element> elem = do_QueryReferent(candidates->ElementAt(i));
      if (!elem) {
        continue;
      }

      reactionsStack->EnqueueUpgradeReaction(elem, aDefinition);
    }
  }
}

JSObject*
CustomElementRegistry::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  return CustomElementRegistryBinding::Wrap(aCx, this, aGivenProto);
}

nsISupports* CustomElementRegistry::GetParentObject() const
{
  return mWindow;
}

DocGroup*
CustomElementRegistry::GetDocGroup() const
{
  return mWindow ? mWindow->GetDocGroup() : nullptr;
}

static const char* kLifeCycleCallbackNames[] = {
  "connectedCallback",
  "disconnectedCallback",
  "adoptedCallback",
  "attributeChangedCallback"
};

static void
CheckLifeCycleCallbacks(JSContext* aCx,
                        JS::Handle<JSObject*> aConstructor,
                        ErrorResult& aRv)
{
  for (size_t i = 0; i < ArrayLength(kLifeCycleCallbackNames); ++i) {
    const char* callbackName = kLifeCycleCallbackNames[i];
    JS::Rooted<JS::Value> callbackValue(aCx);
    if (!JS_GetProperty(aCx, aConstructor, callbackName, &callbackValue)) {
      aRv.StealExceptionFromJSContext(aCx);
      return;
    }
    if (!callbackValue.isUndefined()) {
      if (!callbackValue.isObject()) {
        aRv.ThrowTypeError<MSG_NOT_OBJECT>(NS_ConvertASCIItoUTF16(callbackName));
        return;
      }
      JS::Rooted<JSObject*> callback(aCx, &callbackValue.toObject());
      if (!JS::IsCallable(callback)) {
        aRv.ThrowTypeError<MSG_NOT_CALLABLE>(NS_ConvertASCIItoUTF16(callbackName));
        return;
      }
    }
  }
}

// https://html.spec.whatwg.org/multipage/scripting.html#element-definition
void
CustomElementRegistry::Define(const nsAString& aName,
                              Function& aFunctionConstructor,
                              const ElementDefinitionOptions& aOptions,
                              ErrorResult& aRv)
{
  aRv.MightThrowJSException();

  AutoJSAPI jsapi;
  if (NS_WARN_IF(!jsapi.Init(mWindow))) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  JSContext *cx = jsapi.cx();
  JS::Rooted<JSObject*> constructor(cx, aFunctionConstructor.Callable());

  /**
   * 1. If IsConstructor(constructor) is false, then throw a TypeError and abort
   *    these steps.
   */
  // For now, all wrappers are constructable if they are callable. So we need to
  // unwrap constructor to check it is really constructable.
  JS::Rooted<JSObject*> constructorUnwrapped(cx, js::CheckedUnwrap(constructor));
  if (!constructorUnwrapped) {
    // If the caller's compartment does not have permission to access the
    // unwrapped constructor then throw.
    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
    return;
  }

  if (!JS::IsConstructor(constructorUnwrapped)) {
    aRv.ThrowTypeError<MSG_NOT_CONSTRUCTOR>(NS_LITERAL_STRING("Argument 2 of CustomElementRegistry.define"));
    return;
  }

  /**
   * 2. If name is not a valid custom element name, then throw a "SyntaxError"
   *    DOMException and abort these steps.
   */
  nsCOMPtr<nsIAtom> nameAtom(NS_Atomize(aName));
  if (!nsContentUtils::IsCustomElementName(nameAtom)) {
    aRv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
    return;
  }

  /**
   * 3. If this CustomElementRegistry contains an entry with name name, then
   *    throw a "NotSupportedError" DOMException and abort these steps.
   */
  if (mCustomDefinitions.GetWeak(nameAtom)) {
    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
    return;
  }

  /**
   * 4. If this CustomElementRegistry contains an entry with constructor constructor,
   *    then throw a "NotSupportedError" DOMException and abort these steps.
   */
  const auto& ptr = mConstructors.lookup(constructorUnwrapped);
  if (ptr) {
    MOZ_ASSERT(mCustomDefinitions.GetWeak(ptr->value()),
               "Definition must be found in mCustomDefinitions");
    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
    return;
  }

  /**
   * 5. Let localName be name.
   * 6. Let extends be the value of the extends member of options, or null if
   *    no such member exists.
   * 7. If extends is not null, then:
   *    1. If extends is a valid custom element name, then throw a
   *       "NotSupportedError" DOMException.
   *    2. If the element interface for extends and the HTML namespace is
   *       HTMLUnknownElement (e.g., if extends does not indicate an element
   *       definition in this specification), then throw a "NotSupportedError"
   *       DOMException.
   *    3. Set localName to extends.
   */
  nsAutoString localName(aName);
  if (aOptions.mExtends.WasPassed()) {
    nsCOMPtr<nsIAtom> extendsAtom(NS_Atomize(aOptions.mExtends.Value()));
    if (nsContentUtils::IsCustomElementName(extendsAtom)) {
      aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
      return;
    }

    // bgsound and multicol are unknown html element.
    int32_t tag = nsHTMLTags::CaseSensitiveAtomTagToId(extendsAtom);
    if (tag == eHTMLTag_userdefined ||
        tag == eHTMLTag_bgsound ||
        tag == eHTMLTag_multicol) {
      aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
      return;
    }

    localName.Assign(aOptions.mExtends.Value());
  }

  /**
   * 8. If this CustomElementRegistry's element definition is running flag is set,
   *    then throw a "NotSupportedError" DOMException and abort these steps.
   */
  if (mIsCustomDefinitionRunning) {
    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
    return;
  }

  JS::Rooted<JSObject*> constructorPrototype(cx);
  nsAutoPtr<LifecycleCallbacks> callbacksHolder(new LifecycleCallbacks());
  nsCOMArray<nsIAtom> observedAttributes;
  { // Set mIsCustomDefinitionRunning.
    /**
     * 9. Set this CustomElementRegistry's element definition is running flag.
     */
    AutoSetRunningFlag as(this);

    { // Enter constructor's compartment.
      /**
       * 10.1. Let prototype be Get(constructor, "prototype"). Rethrow any exceptions.
       */
      JSAutoCompartment ac(cx, constructor);
      JS::Rooted<JS::Value> prototypev(cx);
      // The .prototype on the constructor passed could be an "expando" of a
      // wrapper. So we should get it from wrapper instead of the underlying
      // object.
      if (!JS_GetProperty(cx, constructor, "prototype", &prototypev)) {
        aRv.StealExceptionFromJSContext(cx);
        return;
      }

      /**
       * 10.2. If Type(prototype) is not Object, then throw a TypeError exception.
       */
      if (!prototypev.isObject()) {
        aRv.ThrowTypeError<MSG_NOT_OBJECT>(NS_LITERAL_STRING("constructor.prototype"));
        return;
      }

      constructorPrototype = &prototypev.toObject();
    } // Leave constructor's compartment.

    JS::Rooted<JSObject*> constructorProtoUnwrapped(cx, js::CheckedUnwrap(constructorPrototype));
    if (!constructorProtoUnwrapped) {
      // If the caller's compartment does not have permission to access the
      // unwrapped prototype then throw.
      aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
      return;
    }

    { // Enter constructorProtoUnwrapped's compartment
      JSAutoCompartment ac(cx, constructorProtoUnwrapped);

      /**
       * 10.3. Let lifecycleCallbacks be a map with the four keys
       *       "connectedCallback", "disconnectedCallback", "adoptedCallback", and
       *       "attributeChangedCallback", each of which belongs to an entry whose
       *       value is null.
       * 10.4. For each of the four keys callbackName in lifecycleCallbacks:
       *       1. Let callbackValue be Get(prototype, callbackName). Rethrow any
       *          exceptions.
       *       2. If callbackValue is not undefined, then set the value of the
       *          entry in lifecycleCallbacks with key callbackName to the result
       *          of converting callbackValue to the Web IDL Function callback type.
       *          Rethrow any exceptions from the conversion.
       */
      // Will do the same checking for the life cycle callbacks from v0 spec.
      CheckLifeCycleCallbacks(cx, constructorProtoUnwrapped, aRv);
      if (aRv.Failed()) {
        return;
      }

      // Note: We call the init from the constructorProtoUnwrapped's compartment
      //       here.
      JS::RootedValue rootedv(cx, JS::ObjectValue(*constructorProtoUnwrapped));
      if (!JS_WrapValue(cx, &rootedv) || !callbacksHolder->Init(cx, rootedv)) {
        aRv.StealExceptionFromJSContext(cx);
        return;
      }

      /**
       * 10.5. Let observedAttributes be an empty sequence<DOMString>.
       * 10.6. If the value of the entry in lifecycleCallbacks with key
       *       "attributeChangedCallback" is not null, then:
       *       1. Let observedAttributesIterable be Get(constructor,
       *          "observedAttributes"). Rethrow any exceptions.
       *       2. If observedAttributesIterable is not undefined, then set
       *          observedAttributes to the result of converting
       *          observedAttributesIterable to a sequence<DOMString>. Rethrow
       *          any exceptions from the conversion.
       */
      if (callbacksHolder->mAttributeChangedCallback.WasPassed()) {
        // Enter constructor's compartment.
        JSAutoCompartment ac(cx, constructor);
        JS::Rooted<JS::Value> observedAttributesIterable(cx);

        if (!JS_GetProperty(cx, constructor, "observedAttributes",
                            &observedAttributesIterable)) {
          aRv.StealExceptionFromJSContext(cx);
          return;
        }

        if (!observedAttributesIterable.isUndefined()) {
          if (!observedAttributesIterable.isObject()) {
            aRv.ThrowTypeError<MSG_NOT_SEQUENCE>(NS_LITERAL_STRING("observedAttributes"));
            return;
          }

          JS::ForOfIterator iter(cx);
          if (!iter.init(observedAttributesIterable, JS::ForOfIterator::AllowNonIterable)) {
            aRv.StealExceptionFromJSContext(cx);
            return;
          }

          if (!iter.valueIsIterable()) {
            aRv.ThrowTypeError<MSG_NOT_SEQUENCE>(NS_LITERAL_STRING("observedAttributes"));
            return;
          }

          JS::Rooted<JS::Value> attribute(cx);
          while (true) {
            bool done;
            if (!iter.next(&attribute, &done)) {
              aRv.StealExceptionFromJSContext(cx);
              return;
            }
            if (done) {
              break;
            }

            nsAutoString attrStr;
            if (!ConvertJSValueToString(cx, attribute, eStringify, eStringify, attrStr)) {
              aRv.StealExceptionFromJSContext(cx);
              return;
            }
            observedAttributes.AppendElement(NS_Atomize(attrStr));
          }
        }
      } // Leave constructor's compartment.
    } // Leave constructorProtoUnwrapped's compartment.
  } // Unset mIsCustomDefinitionRunning

  /**
   * 11. Let definition be a new custom element definition with name name,
   *     local name localName, constructor constructor, prototype prototype,
   *     observed attributes observedAttributes, and lifecycle callbacks
   *     lifecycleCallbacks.
   */
  // Associate the definition with the custom element.
  nsCOMPtr<nsIAtom> localNameAtom(NS_Atomize(localName));
  LifecycleCallbacks* callbacks = callbacksHolder.forget();

  /**
   * 12. Add definition to this CustomElementRegistry.
   */
  if (!mConstructors.put(constructorUnwrapped, nameAtom)) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  RefPtr<CustomElementDefinition> definition =
    new CustomElementDefinition(nameAtom,
                                localNameAtom,
                                &aFunctionConstructor,
                                Move(observedAttributes),
                                constructorPrototype,
                                callbacks,
                                0 /* TODO dependent on HTML imports. Bug 877072 */);

  CustomElementDefinition* def = definition.get();
  mCustomDefinitions.Put(nameAtom, definition.forget());

  MOZ_ASSERT(mCustomDefinitions.Count() == mConstructors.count(),
             "Number of entries should be the same");

  /**
   * 13. 14. 15. Upgrade candidates
   */
  UpgradeCandidates(nameAtom, def, aRv);

  /**
   * 16. If this CustomElementRegistry's when-defined promise map contains an
   *     entry with key name:
   *     1. Let promise be the value of that entry.
   *     2. Resolve promise with undefined.
   *     3. Delete the entry with key name from this CustomElementRegistry's
   *        when-defined promise map.
   */
  RefPtr<Promise> promise;
  mWhenDefinedPromiseMap.Remove(nameAtom, getter_AddRefs(promise));
  if (promise) {
    promise->MaybeResolveWithUndefined();
  }

}

void
CustomElementRegistry::Get(JSContext* aCx, const nsAString& aName,
                           JS::MutableHandle<JS::Value> aRetVal)
{
  nsCOMPtr<nsIAtom> nameAtom(NS_Atomize(aName));
  CustomElementDefinition* data = mCustomDefinitions.GetWeak(nameAtom);

  if (!data) {
    aRetVal.setUndefined();
    return;
  }

  aRetVal.setObjectOrNull(data->mConstructor->Callable());
  return;
}

already_AddRefed<Promise>
CustomElementRegistry::WhenDefined(const nsAString& aName, ErrorResult& aRv)
{
  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(mWindow);
  RefPtr<Promise> promise = Promise::Create(global, aRv);

  if (aRv.Failed()) {
    return nullptr;
  }

  nsCOMPtr<nsIAtom> nameAtom(NS_Atomize(aName));
  if (!nsContentUtils::IsCustomElementName(nameAtom)) {
    promise->MaybeReject(NS_ERROR_DOM_SYNTAX_ERR);
    return promise.forget();
  }

  if (mCustomDefinitions.GetWeak(nameAtom)) {
    promise->MaybeResolve(JS::UndefinedHandleValue);
    return promise.forget();
  }

  if (mWhenDefinedPromiseMap.Contains(nameAtom)) {
    mWhenDefinedPromiseMap.Get(nameAtom, getter_AddRefs(promise));
  } else {
    mWhenDefinedPromiseMap.Put(nameAtom, promise);
  }

  return promise.forget();
}

namespace {

static void
DoUpgrade(Element* aElement,
          CustomElementConstructor* aConstructor,
          ErrorResult& aRv)
{
  // Rethrow the exception since it might actually throw the exception from the
  // upgrade steps back out to the caller of document.createElement.
  RefPtr<Element> constructResult =
    aConstructor->Construct("Custom Element Upgrade", aRv);
  if (aRv.Failed()) {
    return;
  }

  if (!constructResult || constructResult.get() != aElement) {
    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
    return;
  }
}

} // anonymous namespace

// https://html.spec.whatwg.org/multipage/scripting.html#upgrades
/* static */ void
CustomElementRegistry::Upgrade(Element* aElement,
                               CustomElementDefinition* aDefinition,
                               ErrorResult& aRv)
{
  RefPtr<CustomElementData> data = aElement->GetCustomElementData();
  MOZ_ASSERT(data, "CustomElementData should exist");

  // Step 1 and step 2.
  if (data->mState == CustomElementData::State::eCustom ||
      data->mState == CustomElementData::State::eFailed) {
    return;
  }

  // Step 3.
  if (!aDefinition->mObservedAttributes.IsEmpty()) {
    uint32_t count = aElement->GetAttrCount();
    for (uint32_t i = 0; i < count; i++) {
      mozilla::dom::BorrowedAttrInfo info = aElement->GetAttrInfoAt(i);

      const nsAttrName* name = info.mName;
      nsIAtom* attrName = name->LocalName();

      if (aDefinition->IsInObservedAttributeList(attrName)) {
        int32_t namespaceID = name->NamespaceID();
        nsAutoString attrValue, namespaceURI;
        info.mValue->ToString(attrValue);
        nsContentUtils::NameSpaceManager()->GetNameSpaceURI(namespaceID,
                                                            namespaceURI);

        LifecycleCallbackArgs args = {
          nsDependentAtomString(attrName),
          NullString(),
          attrValue,
          (namespaceURI.IsEmpty() ? NullString() : namespaceURI)
        };
        nsContentUtils::EnqueueLifecycleCallback(nsIDocument::eAttributeChanged,
                                                 aElement,
                                                 &args, nullptr, aDefinition);
      }
    }
  }

  // Step 4.
  if (aElement->IsInComposedDoc()) {
    nsContentUtils::EnqueueLifecycleCallback(nsIDocument::eConnected, aElement,
                                             nullptr, nullptr, aDefinition);
  }

  // Step 5.
  AutoConstructionStackEntry acs(aDefinition->mConstructionStack,
                                 nsGenericHTMLElement::FromContent(aElement));

  // Step 6 and step 7.
  DoUpgrade(aElement, aDefinition->mConstructor, aRv);
  if (aRv.Failed()) {
    data->mState = CustomElementData::State::eFailed;
    // Empty element's custom element reaction queue.
    data->mReactionQueue.Clear();
    return;
  }

  // Step 8.
  data->mState = CustomElementData::State::eCustom;

  // Step 9.
  aElement->SetCustomElementDefinition(aDefinition);
}

//-----------------------------------------------------
// CustomElementReactionsStack

void
CustomElementReactionsStack::CreateAndPushElementQueue()
{
  MOZ_ASSERT(mRecursionDepth);
  MOZ_ASSERT(!mIsElementQueuePushedForCurrentRecursionDepth);

  // Push a new element queue onto the custom element reactions stack.
  mReactionsStack.AppendElement(MakeUnique<ElementQueue>());
  mIsElementQueuePushedForCurrentRecursionDepth = true;
}

void
CustomElementReactionsStack::PopAndInvokeElementQueue()
{
  MOZ_ASSERT(mRecursionDepth);
  MOZ_ASSERT(mIsElementQueuePushedForCurrentRecursionDepth);
  MOZ_ASSERT(!mReactionsStack.IsEmpty(),
             "Reaction stack shouldn't be empty");

  // Pop the element queue from the custom element reactions stack,
  // and invoke custom element reactions in that queue.
  const uint32_t lastIndex = mReactionsStack.Length() - 1;
  ElementQueue* elementQueue = mReactionsStack.ElementAt(lastIndex).get();
  // Check element queue size in order to reduce function call overhead.
  if (!elementQueue->IsEmpty()) {
    // It is still not clear what error reporting will look like in custom
    // element, see https://github.com/w3c/webcomponents/issues/635.
    // We usually report the error to entry global in gecko, so just follow the
    // same behavior here.
    // This may be null if it's called from parser, see the case of
    // attributeChangedCallback in
    // https://html.spec.whatwg.org/multipage/parsing.html#create-an-element-for-the-token
    // In that case, the exception of callback reactions will be automatically
    // reported in CallSetup.
    nsIGlobalObject* global = GetEntryGlobal();
    InvokeReactions(elementQueue, global);
  }

  // InvokeReactions() might create other custom element reactions, but those
  // new reactions should be already consumed and removed at this point.
  MOZ_ASSERT(lastIndex == mReactionsStack.Length() - 1,
             "reactions created by InvokeReactions() should be consumed and removed");

  mReactionsStack.RemoveElementAt(lastIndex);
  mIsElementQueuePushedForCurrentRecursionDepth = false;
}

void
CustomElementReactionsStack::EnqueueUpgradeReaction(Element* aElement,
                                                    CustomElementDefinition* aDefinition)
{
  Enqueue(aElement, new CustomElementUpgradeReaction(aDefinition));
}

void
CustomElementReactionsStack::EnqueueCallbackReaction(Element* aElement,
                                                     UniquePtr<CustomElementCallback> aCustomElementCallback)
{
  Enqueue(aElement, new CustomElementCallbackReaction(Move(aCustomElementCallback)));
}

void
CustomElementReactionsStack::Enqueue(Element* aElement,
                                     CustomElementReaction* aReaction)
{
  RefPtr<CustomElementData> elementData = aElement->GetCustomElementData();
  MOZ_ASSERT(elementData, "CustomElementData should exist");

  if (mRecursionDepth) {
    // If the element queue is not created for current recursion depth, create
    // and push an element queue to reactions stack first.
    if (!mIsElementQueuePushedForCurrentRecursionDepth) {
      CreateAndPushElementQueue();
    }

    MOZ_ASSERT(!mReactionsStack.IsEmpty());
    // Add element to the current element queue.
    mReactionsStack.LastElement()->AppendElement(aElement);
    elementData->mReactionQueue.AppendElement(aReaction);
    return;
  }

  // If the custom element reactions stack is empty, then:
  // Add element to the backup element queue.
  MOZ_ASSERT(mReactionsStack.IsEmpty(),
             "custom element reactions stack should be empty");
  MOZ_ASSERT(!aReaction->IsUpgradeReaction(),
             "Upgrade reaction should not be scheduled to backup queue");
  mBackupQueue.AppendElement(aElement);
  elementData->mReactionQueue.AppendElement(aReaction);

  if (mIsBackupQueueProcessing) {
    return;
  }

  CycleCollectedJSContext* context = CycleCollectedJSContext::Get();
  RefPtr<BackupQueueMicroTask> bqmt = new BackupQueueMicroTask(this);
  context->DispatchMicroTaskRunnable(bqmt.forget());
}

void
CustomElementReactionsStack::InvokeBackupQueue()
{
  // Check backup queue size in order to reduce function call overhead.
  if (!mBackupQueue.IsEmpty()) {
    // Upgrade reactions won't be scheduled in backup queue and the exception of
    // callback reactions will be automatically reported in CallSetup.
    // If the reactions are invoked from backup queue (in microtask check point),
    // we don't need to pass global object for error reporting.
    InvokeReactions(&mBackupQueue, nullptr);
  }
  MOZ_ASSERT(mBackupQueue.IsEmpty(),
             "There are still some reactions in BackupQueue not being consumed!?!");
}

void
CustomElementReactionsStack::InvokeReactions(ElementQueue* aElementQueue,
                                             nsIGlobalObject* aGlobal)
{
  // This is used for error reporting.
  Maybe<AutoEntryScript> aes;
  if (aGlobal) {
    aes.emplace(aGlobal, "custom elements reaction invocation");
  }

  // Note: It's possible to re-enter this method.
  for (uint32_t i = 0; i < aElementQueue->Length(); ++i) {
    Element* element = aElementQueue->ElementAt(i);

    // ElementQueue hold a element's strong reference, it should not be a nullptr.
    MOZ_ASSERT(element);

    RefPtr<CustomElementData> elementData = element->GetCustomElementData();
    if (!elementData) {
      // This happens when the document is destroyed and the element is already
      // unlinked, no need to fire the callbacks in this case.
      continue;
    }

    auto& reactions = elementData->mReactionQueue;
    for (uint32_t j = 0; j < reactions.Length(); ++j) {
      // Transfer the ownership of the entry due to reentrant invocation of
      // this funciton. The entry will be removed when bug 1379573 is landed.
      auto reaction(Move(reactions.ElementAt(j)));
      if (reaction) {
        ErrorResult rv;
        reaction->Invoke(element, rv);
        if (aes) {
          JSContext* cx = aes->cx();
          if (rv.MaybeSetPendingException(cx)) {
            aes->ReportException();
          }
          MOZ_ASSERT(!JS_IsExceptionPending(cx));
        }
        MOZ_ASSERT(!rv.Failed());
      }
    }
    reactions.Clear();
  }
  aElementQueue->Clear();
}

//-----------------------------------------------------
// CustomElementDefinition

NS_IMPL_CYCLE_COLLECTION_CLASS(CustomElementDefinition)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(CustomElementDefinition)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mConstructor)
  tmp->mPrototype = nullptr;
  tmp->mCallbacks = nullptr;
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CustomElementDefinition)
  mozilla::dom::LifecycleCallbacks* callbacks = tmp->mCallbacks.get();

  if (callbacks->mAttributeChangedCallback.WasPassed()) {
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb,
      "mCallbacks->mAttributeChangedCallback");
    cb.NoteXPCOMChild(callbacks->mAttributeChangedCallback.Value());
  }

  if (callbacks->mConnectedCallback.WasPassed()) {
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mCallbacks->mConnectedCallback");
    cb.NoteXPCOMChild(callbacks->mConnectedCallback.Value());
  }

  if (callbacks->mDisconnectedCallback.WasPassed()) {
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mCallbacks->mDisconnectedCallback");
    cb.NoteXPCOMChild(callbacks->mDisconnectedCallback.Value());
  }

  if (callbacks->mAdoptedCallback.WasPassed()) {
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mCallbacks->mAdoptedCallback");
    cb.NoteXPCOMChild(callbacks->mAdoptedCallback.Value());
  }

  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mConstructor");
  cb.NoteXPCOMChild(tmp->mConstructor);
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(CustomElementDefinition)
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mPrototype)
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(CustomElementDefinition, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(CustomElementDefinition, Release)

CustomElementDefinition::CustomElementDefinition(nsIAtom* aType,
                                                 nsIAtom* aLocalName,
                                                 Function* aConstructor,
                                                 nsCOMArray<nsIAtom>&& aObservedAttributes,
                                                 JSObject* aPrototype,
                                                 LifecycleCallbacks* aCallbacks,
                                                 uint32_t aDocOrder)
  : mType(aType),
    mLocalName(aLocalName),
    mConstructor(new CustomElementConstructor(aConstructor)),
    mObservedAttributes(Move(aObservedAttributes)),
    mPrototype(aPrototype),
    mCallbacks(aCallbacks),
    mDocOrder(aDocOrder)
{
}

//-----------------------------------------------------
// CustomElementUpgradeReaction

/* virtual */ void
CustomElementUpgradeReaction::Invoke(Element* aElement, ErrorResult& aRv)
{
  CustomElementRegistry::Upgrade(aElement, mDefinition, aRv);
}

//-----------------------------------------------------
// CustomElementCallbackReaction

/* virtual */ void
CustomElementCallbackReaction::Invoke(Element* aElement, ErrorResult& aRv)
{
  mCustomElementCallback->Call();
}

} // namespace dom
} // namespace mozilla