summaryrefslogtreecommitdiffstats
path: root/layout/base/nsCSSFrameConstructor.h
blob: 89e5594e4f3096c6baf3adaa8834975b8c2bd0e7 (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
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
/* -*- Mode: C++; 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/. */

/*
 * construction of a frame tree that is nearly isomorphic to the content
 * tree and updating of that tree in response to dynamic changes
 */

#ifndef nsCSSFrameConstructor_h___
#define nsCSSFrameConstructor_h___

#include "mozilla/Attributes.h"
#include "mozilla/LinkedList.h"
#include "mozilla/RestyleManagerBase.h"
#include "mozilla/RestyleManagerHandle.h"

#include "nsCOMPtr.h"
#include "nsILayoutHistoryState.h"
#include "nsQuoteList.h"
#include "nsCounterManager.h"
#include "nsIAnonymousContentCreator.h"
#include "nsFrameManager.h"
#include "ScrollbarStyles.h"

struct nsFrameItems;
class nsStyleContext;
struct nsStyleDisplay;
struct nsGenConInitializer;

class nsContainerFrame;
class nsFirstLineFrame;
class nsICSSAnonBoxPseudo;
class nsIDocument;
class nsPageContentFrame;
struct PendingBinding;
class nsGenericDOMDataNode;

class nsFrameConstructorState;

namespace mozilla {

namespace dom {

class FlattenedChildIterator;

} // namespace dom
} // namespace mozilla

class nsCSSFrameConstructor : public nsFrameManager
{
public:
  typedef mozilla::CSSPseudoElementType CSSPseudoElementType;
  typedef mozilla::dom::Element Element;

  friend class mozilla::RestyleManager;
  friend class mozilla::RestyleManagerBase;
  friend class mozilla::ServoRestyleManager;

  nsCSSFrameConstructor(nsIDocument* aDocument, nsIPresShell* aPresShell);
  ~nsCSSFrameConstructor(void) {
    NS_ASSERTION(mUpdateCount == 0, "Dying in the middle of our own update?");
  }

  // get the alternate text for a content node
  static void GetAlternateTextFor(nsIContent*    aContent,
                                  nsIAtom*       aTag,  // content object's tag
                                  nsXPIDLString& aAltText);

private:
  nsCSSFrameConstructor(const nsCSSFrameConstructor& aCopy) = delete;
  nsCSSFrameConstructor& operator=(const nsCSSFrameConstructor& aCopy) = delete;

public:
  mozilla::RestyleManagerHandle RestyleManager() const
    { return mPresShell->GetPresContext()->RestyleManager(); }

  nsIFrame* ConstructRootFrame();

  nsresult ReconstructDocElementHierarchy();

  // Create frames for content nodes that are marked as needing frames. This
  // should be called before ProcessPendingRestyles.
  // Note: It's the caller's responsibility to make sure to wrap a
  // CreateNeededFrames call in a view update batch and a script blocker.
  void CreateNeededFrames();

private:
  void CreateNeededFrames(nsIContent* aContent);

  enum Operation {
    CONTENTAPPEND,
    CONTENTINSERT
  };

  // aChild is the child being inserted for inserts, and the first
  // child being appended for appends.
  bool MaybeConstructLazily(Operation aOperation,
                              nsIContent* aContainer,
                              nsIContent* aChild);

  // Issues a single ContentInserted for each child of aContainer in the range
  // [aStartChild, aEndChild).
  void IssueSingleInsertNofications(nsIContent* aContainer,
                                    nsIContent* aStartChild,
                                    nsIContent* aEndChild,
                                    bool aAllowLazyConstruction);

  /**
   * Data that represents an insertion point for some child content.
   */
  struct InsertionPoint
  {
    InsertionPoint()
      : mParentFrame(nullptr), mContainer(nullptr), mMultiple(false) {}
    InsertionPoint(nsContainerFrame* aParentFrame, nsIContent* aContainer,
                   bool aMultiple = false)
      : mParentFrame(aParentFrame), mContainer(aContainer),
        mMultiple(aMultiple) {}
    /**
     * The parent frame to use if the inserted children needs to create
     * frame(s).  May be null, which signals that  we shouldn't try to
     * create frames for the inserted children; either because there are
     * no parent frame or because there are multiple insertion points and
     * we will call IssueSingleInsertNofications for each child instead.
     * mContainer should not be used when mParentFrame is null.
     */
    nsContainerFrame* mParentFrame;
    /**
     * The flattened tree parent for the inserted children.
     * It's undefined if mParentFrame is null.
     */
    nsIContent* mContainer;
    /**
     * If true then there are multiple insertion points, which means consumers
     * should insert children individually into the node's flattened tree parent.
     */
    bool mMultiple;
  };
  /**
   * Checks if the children of aContainer in the range [aStartChild, aEndChild)
   * can be inserted/appended to one insertion point together. If so, returns
   * that insertion point. If not, returns with InsertionPoint.mFrame == nullptr
   * and issues single ContentInserted calls for each child.
   * aEndChild = nullptr indicates that we are dealing with an append.
   */
  InsertionPoint GetRangeInsertionPoint(nsIContent* aContainer,
                                        nsIContent* aStartChild,
                                        nsIContent* aEndChild,
                                        bool aAllowLazyConstruction);

  // Returns true if parent was recreated due to frameset child, false otherwise.
  bool MaybeRecreateForFrameset(nsIFrame* aParentFrame,
                                  nsIContent* aStartChild,
                                  nsIContent* aEndChild);

public:
  /**
   * Lazy frame construction is controlled by the aAllowLazyConstruction bool
   * parameter of nsCSSFrameConstructor::ContentAppended/Inserted. It is true
   * for all inserts/appends as passed from the presshell, except for the
   * insert of the root element, which is always non-lazy. Even if the
   * aAllowLazyConstruction passed to ContentAppended/Inserted is true we still
   * may not be able to construct lazily, so we call MaybeConstructLazily.
   * MaybeConstructLazily does not allow lazy construction if any of the
   * following are true:
   *  -we are in chrome
   *  -the container is in a native anonymous subtree
   *  -the container is XUL
   *  -is any of the appended/inserted nodes are XUL or editable
   *  -(for inserts) the child is anonymous.  In the append case this function
   *   must not be called with anonymous children.
   * The XUL and chrome checks are because XBL bindings only get applied at
   * frame construction time and some things depend on the bindings getting
   * attached synchronously. The editable checks are because the editor seems
   * to expect frames to be constructed synchronously.
   *
   * If MaybeConstructLazily returns false we construct as usual, but if it
   * returns true then it adds NODE_NEEDS_FRAME bits to the newly
   * inserted/appended nodes and adds NODE_DESCENDANTS_NEED_FRAMES bits to the
   * container and up along the parent chain until it hits the root or another
   * node with that bit set. Then it posts a restyle event to ensure that a
   * flush happens to construct those frames.
   *
   * When the flush happens the presshell calls
   * nsCSSFrameConstructor::CreateNeededFrames. CreateNeededFrames follows any
   * nodes with NODE_DESCENDANTS_NEED_FRAMES set down the content tree looking
   * for nodes with NODE_NEEDS_FRAME set. It calls ContentAppended for any runs
   * of nodes with NODE_NEEDS_FRAME set that are at the end of their childlist,
   * and ContentRangeInserted for any other runs that aren't.
   *
   * If a node is removed from the document then we don't bother unsetting any
   * of the lazy bits that might be set on it, its descendants, or any of its
   * ancestor nodes because that is a slow operation, the work might be wasted
   * if another node gets inserted in its place, and we can clear the bits
   * quicker by processing the content tree from top down the next time we call
   * CreateNeededFrames. (We do clear the bits when BindToTree is called on any
   * nsIContent; so any nodes added to the document will not have any lazy bits
   * set.)
   */

  // If aAllowLazyConstruction is true then frame construction of the new
  // children can be done lazily.
  nsresult ContentAppended(nsIContent* aContainer,
                           nsIContent* aFirstNewContent,
                           bool        aAllowLazyConstruction);

  // If aAllowLazyConstruction is true then frame construction of the new child
  // can be done lazily.
  nsresult ContentInserted(nsIContent*            aContainer,
                           nsIContent*            aChild,
                           nsILayoutHistoryState* aFrameState,
                           bool                   aAllowLazyConstruction);

  // Like ContentInserted but handles inserting the children of aContainer in
  // the range [aStartChild, aEndChild).  aStartChild must be non-null.
  // aEndChild may be null to indicate the range includes all kids after
  // aStartChild.  If aAllowLazyConstruction is true then frame construction of
  // the new children can be done lazily. It is only allowed to be true when
  // inserting a single node.
  nsresult ContentRangeInserted(nsIContent*            aContainer,
                                nsIContent*            aStartChild,
                                nsIContent*            aEndChild,
                                nsILayoutHistoryState* aFrameState,
                                bool                   aAllowLazyConstruction);

  enum RemoveFlags {
    REMOVE_CONTENT, REMOVE_FOR_RECONSTRUCTION, REMOVE_DESTROY_FRAMES };
  /**
   * Recreate or destroy frames for aChild in aContainer.
   * aFlags == REMOVE_CONTENT means aChild has been removed from the document.
   * aFlags == REMOVE_FOR_RECONSTRUCTION means the caller will reconstruct the
   *   frames later.
   * In both the above cases, this method will in some cases try to reconstruct
   * the frames (aDidReconstruct is then set to true), it's just that in the
   * former case aChild isn't in the document so no frames will be created for
   * it.  Ancestors may have been reframed though.
   * aFlags == REMOVE_DESTROY_FRAMES is the same as REMOVE_FOR_RECONSTRUCTION
   * except it will never try to reconstruct frames.  Instead, the caller is
   * responsible for doing that, on the content returned in aDestroyedFramesFor.
   * The layout frame state is guarranted to be captured for the removed frames
   * only when aFlags == REMOVE_DESTROY_FRAMES, otherwise it will only be
   * captured if we reconstructed frames for an ancestor.
   */
  nsresult ContentRemoved(nsIContent*  aContainer,
                          nsIContent*  aChild,
                          nsIContent*  aOldNextSibling,
                          RemoveFlags  aFlags,
                          bool*        aDidReconstruct,
                          nsIContent** aDestroyedFramesFor = nullptr);

  nsresult CharacterDataChanged(nsIContent* aContent,
                                CharacterDataChangeInfo* aInfo);

  // If aContent is a text node that has been optimized away due to being
  // whitespace next to a block boundary (or for some other reason), stop
  // doing that and create a frame for it if it should have one. This recreates
  // frames so be careful (although this should not change actual layout).
  // Returns the frame for aContent if there is one.
  nsIFrame* EnsureFrameForTextNode(nsGenericDOMDataNode* aContent);

  // generate the child frames and process bindings
  nsresult GenerateChildFrames(nsContainerFrame* aFrame);

  // Should be called when a frame is going to be destroyed and
  // WillDestroyFrameTree hasn't been called yet.
  void NotifyDestroyingFrame(nsIFrame* aFrame);

  void BeginUpdate();
  void EndUpdate();
  void RecalcQuotesAndCounters();

  // Called when any counter style is changed.
  void NotifyCounterStylesAreDirty();

  // Gets called when the presshell is destroying itself and also
  // when we tear down our frame tree to reconstruct it
  void WillDestroyFrameTree();

  /**
   * Destroy the frames for aContent.  Note that this may destroy frames
   * for an ancestor instead - aDestroyedFramesFor contains the content node
   * where frames were actually destroyed (which should be used in the
   * ContentInserted call to recreate frames).  The frame tree state
   * is captured before the frames are destroyed and can be retrieved using
   * GetLastCapturedLayoutHistoryState().
   */
  void DestroyFramesFor(nsIContent*  aContent,
                        nsIContent** aDestroyedFramesFor);

  // Request to create a continuing frame.  This method never returns null.
  nsIFrame* CreateContinuingFrame(nsPresContext*    aPresContext,
                                  nsIFrame*         aFrame,
                                  nsContainerFrame* aParentFrame,
                                  bool              aIsFluid = true);

  // Copy over fixed frames from aParentFrame's prev-in-flow
  nsresult ReplicateFixedFrames(nsPageContentFrame* aParentFrame);

  /**
   * Get the XBL insertion point for aChild in aContainer.
   */
  InsertionPoint GetInsertionPoint(nsIContent* aContainer, nsIContent* aChild);

  nsresult CreateListBoxContent(nsContainerFrame* aParentFrame,
                                nsIFrame*         aPrevFrame,
                                nsIContent*       aChild,
                                nsIFrame**        aResult,
                                bool              aIsAppend);

  // GetInitialContainingBlock() is deprecated in favor of GetRootElementFrame();
  // nsIFrame* GetInitialContainingBlock() { return mRootElementFrame; }
  // This returns the outermost frame for the root element
  nsContainerFrame* GetRootElementFrame() { return mRootElementFrame; }
  // This returns the frame for the root element that does not
  // have a psuedo-element style
  nsIFrame* GetRootElementStyleFrame() { return mRootElementStyleFrame; }
  nsIFrame* GetPageSequenceFrame() { return mPageSequenceFrame; }

  // Get the frame that is the parent of the root element.
  nsContainerFrame* GetDocElementContainingBlock()
    { return mDocElementContainingBlock; }

  /**
   * Return the layout history state that was captured in the last
   * ContentRemoved / RecreateFramesForContent call.
   */
  nsILayoutHistoryState* GetLastCapturedLayoutHistoryState()
  {
    return mTempFrameTreeState;
  }

private:
  struct FrameConstructionItem;
  class FrameConstructionItemList;

  nsContainerFrame* ConstructPageFrame(nsIPresShell*      aPresShell,
                                       nsContainerFrame*  aParentFrame,
                                       nsIFrame*          aPrevPageFrame,
                                       nsContainerFrame*& aCanvasFrame);

  void InitAndRestoreFrame (const nsFrameConstructorState& aState,
                            nsIContent*                    aContent,
                            nsContainerFrame*              aParentFrame,
                            nsIFrame*                      aNewFrame,
                            bool                           aAllowCounters = true);

  // aState can be null if not available; it's used as an optimization.
  // XXXbz IsValidSibling is the only caller that doesn't pass a state here!
  already_AddRefed<nsStyleContext>
  ResolveStyleContext(nsIFrame*                aParentFrame,
                      nsIContent*              aContainer,
                      nsIContent*              aChild,
                      nsFrameConstructorState* aState);
  already_AddRefed<nsStyleContext>
  ResolveStyleContext(nsIFrame*                aParentFrame,
                      nsIContent*              aChild,
                      nsFrameConstructorState* aState);
  already_AddRefed<nsStyleContext>
  ResolveStyleContext(const InsertionPoint&    aInsertion,
                      nsIContent*              aChild,
                      nsFrameConstructorState* aState);
  already_AddRefed<nsStyleContext>
  ResolveStyleContext(nsStyleContext*          aParentStyleContext,
                      nsIContent*              aContent,
                      nsFrameConstructorState* aState);

  // Add the frame construction items for the given aContent and aParentFrame
  // to the list.  This might add more than one item in some rare cases.
  // If aSuppressWhiteSpaceOptimizations is true, optimizations that
  // may suppress the construction of white-space-only text frames
  // must be skipped for these items and items around them.
  void AddFrameConstructionItems(nsFrameConstructorState& aState,
                                 nsIContent*              aContent,
                                 bool                     aSuppressWhiteSpaceOptimizations,
                                 const InsertionPoint&    aInsertion,
                                 FrameConstructionItemList& aItems);

  // Helper method for AddFrameConstructionItems etc.
  // Unsets the need-frame/restyle bits on aContent.
  // return true iff we should attempt to create frames for aContent.
  bool ShouldCreateItemsForChild(nsFrameConstructorState& aState,
                                 nsIContent* aContent,
                                 nsContainerFrame* aParentFrame);

  // Helper method for AddFrameConstructionItems etc.
  // Make sure ShouldCreateItemsForChild() returned true before calling this.
  void DoAddFrameConstructionItems(nsFrameConstructorState& aState,
                                   nsIContent* aContent,
                                   nsStyleContext* aStyleContext,
                                   bool aSuppressWhiteSpaceOptimizations,
                                   nsContainerFrame* aParentFrame,
                                   nsTArray<nsIAnonymousContentCreator::ContentInfo>* aAnonChildren,
                                   FrameConstructionItemList& aItems);

  // Construct the frames for the document element.  This can return null if the
  // document element is display:none, or if the document element has a
  // not-yet-loaded XBL binding, or if it's an SVG element that's not <svg>.
  nsIFrame* ConstructDocElementFrame(Element*                 aDocElement,
                                     nsILayoutHistoryState*   aFrameState);

  // Set up our mDocElementContainingBlock correctly for the given root
  // content.
  void SetUpDocElementContainingBlock(nsIContent* aDocElement);

  /**
   * CreateAttributeContent creates a single content/frame combination for an
   * |attr(foo)| generated content.
   *
   * @param aParentContent the parent content for the generated content
   * @param aParentFrame the parent frame for the generated frame
   * @param aAttrNamespace the namespace of the attribute in question
   * @param aAttrName the localname of the attribute
   * @param aStyleContext the style context to use
   * @param aGeneratedContent the array of generated content to append the
   *                          created content to.
   * @param [out] aNewContent the content node we create
   * @param [out] aNewFrame the new frame we create
   */
  nsresult CreateAttributeContent(nsIContent* aParentContent,
                                  nsIFrame* aParentFrame,
                                  int32_t aAttrNamespace,
                                  nsIAtom* aAttrName,
                                  nsStyleContext* aStyleContext,
                                  nsCOMArray<nsIContent>& aGeneratedContent,
                                  nsIContent** aNewContent,
                                  nsIFrame** aNewFrame);

  /**
   * Create a text node containing the given string. If aText is non-null
   * then we also set aText to the returned node.
   */
  already_AddRefed<nsIContent> CreateGenConTextNode(nsFrameConstructorState& aState,
                                                    const nsString& aString,
                                                    RefPtr<nsTextNode>* aText,
                                                    nsGenConInitializer* aInitializer);

  /**
   * Create a content node for the given generated content style.
   * The caller takes care of making it SetIsNativeAnonymousRoot, binding it
   * to the document, and creating frames for it.
   * @param aParentContent is the node that has the before/after style
   * @param aStyleContext is the 'before' or 'after' pseudo-element
   * style context
   * @param aContentIndex is the index of the content item to create
   */
  already_AddRefed<nsIContent> CreateGeneratedContent(nsFrameConstructorState& aState,
                                                      nsIContent*     aParentContent,
                                                      nsStyleContext* aStyleContext,
                                                      uint32_t        aContentIndex);

  // aFrame may be null; this method doesn't use it directly in any case.
  void CreateGeneratedContentItem(nsFrameConstructorState&   aState,
                                  nsContainerFrame*          aFrame,
                                  nsIContent*                aContent,
                                  nsStyleContext*            aStyleContext,
                                  CSSPseudoElementType       aPseudoElement,
                                  FrameConstructionItemList& aItems);

  // This method can change aFrameList: it can chop off the beginning and put
  // it in aParentFrame while putting the remainder into a ib-split sibling of
  // aParentFrame.  aPrevSibling must be the frame after which aFrameList is to
  // be placed on aParentFrame's principal child list.  It may be null if
  // aFrameList is being added at the beginning of the child list.
  nsresult AppendFramesToParent(nsFrameConstructorState&       aState,
                                nsContainerFrame*              aParentFrame,
                                nsFrameItems&                  aFrameList,
                                nsIFrame*                      aPrevSibling,
                                bool                           aIsRecursiveCall = false);

  // BEGIN TABLE SECTION
  /**
   * Construct a table wrapper frame. This is the FrameConstructionData
   * callback used for the job.
   */
  nsIFrame* ConstructTable(nsFrameConstructorState& aState,
                           FrameConstructionItem&   aItem,
                           nsContainerFrame*        aParentFrame,
                           const nsStyleDisplay*    aDisplay,
                           nsFrameItems&            aFrameItems);

  /**
   * FrameConstructionData callback for constructing table rows and row groups.
   */
  nsIFrame* ConstructTableRowOrRowGroup(nsFrameConstructorState& aState,
                                        FrameConstructionItem&   aItem,
                                        nsContainerFrame*        aParentFrame,
                                        const nsStyleDisplay*    aStyleDisplay,
                                        nsFrameItems&            aFrameItems);

  /**
   * FrameConstructionData callback used for constructing table columns.
   */
  nsIFrame* ConstructTableCol(nsFrameConstructorState& aState,
                              FrameConstructionItem&   aItem,
                              nsContainerFrame*        aParentFrame,
                              const nsStyleDisplay*    aStyleDisplay,
                              nsFrameItems&            aFrameItems);

  /**
   * FrameConstructionData callback used for constructing table cells.
   */
  nsIFrame* ConstructTableCell(nsFrameConstructorState& aState,
                               FrameConstructionItem&   aItem,
                               nsContainerFrame*        aParentFrame,
                               const nsStyleDisplay*    aStyleDisplay,
                               nsFrameItems&            aFrameItems);

private:
  /* An enum of possible parent types for anonymous table or ruby object 
     construction */
  enum ParentType {
    eTypeBlock = 0, /* This includes all non-table-related frames */
    eTypeRow,
    eTypeRowGroup,
    eTypeColGroup,
    eTypeTable,
    eTypeRuby,
    eTypeRubyBase,
    eTypeRubyBaseContainer,
    eTypeRubyText,
    eTypeRubyTextContainer,
    eParentTypeCount
  };

  /* 4 bits is enough to handle our ParentType values */
#define FCDATA_PARENT_TYPE_OFFSET 28
  /* Macro to get the desired parent type out of an mBits member of
     FrameConstructionData */
#define FCDATA_DESIRED_PARENT_TYPE(_bits)           \
  ParentType((_bits) >> FCDATA_PARENT_TYPE_OFFSET)
  /* Macro to create FrameConstructionData bits out of a desired parent type */
#define FCDATA_DESIRED_PARENT_TYPE_TO_BITS(_type)     \
  (((uint32_t)(_type)) << FCDATA_PARENT_TYPE_OFFSET)

  /* Get the parent type that aParentFrame has. */
  static ParentType GetParentType(nsIFrame* aParentFrame) {
    return GetParentType(aParentFrame->GetType());
  }

  /* Get the parent type for the given nsIFrame type atom */
  static ParentType GetParentType(nsIAtom* aFrameType);

  static bool IsRubyParentType(ParentType aParentType) {
    return (aParentType == eTypeRuby ||
            aParentType == eTypeRubyBase ||
            aParentType == eTypeRubyBaseContainer ||
            aParentType == eTypeRubyText ||
            aParentType == eTypeRubyTextContainer);
  }

  static bool IsTableParentType(ParentType aParentType) {
    return (aParentType == eTypeTable ||
            aParentType == eTypeRow ||
            aParentType == eTypeRowGroup ||
            aParentType == eTypeColGroup);
  }

  /* A constructor function that just creates an nsIFrame object.  The caller
     is responsible for initializing the object, adding it to frame lists,
     constructing frames for the children, etc.

     @param nsIPresShell the presshell whose arena should be used to allocate
                         the frame.
     @param nsStyleContext the style context to use for the frame. */
  typedef nsIFrame* (* FrameCreationFunc)(nsIPresShell*, nsStyleContext*);
  typedef nsContainerFrame* (* ContainerFrameCreationFunc)(nsIPresShell*, nsStyleContext*);
  typedef nsBlockFrame* (* BlockFrameCreationFunc)(nsIPresShell*, nsStyleContext*);

  /* A function that can be used to get a FrameConstructionData.  Such
     a function is allowed to return null.

     @param nsIContent the node for which the frame is being constructed.
     @param nsStyleContext the style context to be used for the frame.
  */
  struct FrameConstructionData;
  typedef const FrameConstructionData*
    (* FrameConstructionDataGetter)(Element*, nsStyleContext*);

  /* A constructor function that's used for complicated construction tasks.
     This is expected to create the new frame, initialize it, add whatever
     needs to be added to aFrameItems (XXXbz is that really necessary?  Could
     caller add?  Might there be cases when the returned frame or its
     placeholder is not the thing that ends up in aFrameItems?  If not, would
     it be safe to do the add into the frame construction state after
     processing kids?  Look into this as a followup!), process children as
     needed, etc.  It is NOT expected to deal with setting the frame on the
     content.

     @param aState the frame construction state to use.
     @param aItem the frame construction item to use
     @param aParentFrame the frame to set as the parent of the
                         newly-constructed frame.
     @param aStyleDisplay the display struct from aItem's mStyleContext
     @param aFrameItems the frame list to add the new frame (or its
                        placeholder) to.
     @return the frame that was constructed.  This frame is what the caller
             will set as the frame on the content.  Guaranteed non-null.
  */
  typedef nsIFrame*
    (nsCSSFrameConstructor::* FrameFullConstructor)(nsFrameConstructorState& aState,
                                                    FrameConstructionItem& aItem,
                                                    nsContainerFrame* aParentFrame,
                                                    const nsStyleDisplay* aStyleDisplay,
                                                    nsFrameItems& aFrameItems);

  /* Bits that modify the way a FrameConstructionData is handled */

  /* If the FCDATA_SKIP_FRAMESET bit is set, then the frame created should not
     be set as the primary frame on the content node.  This should only be used
     in very rare cases when we create more than one frame for a given content
     node. */
#define FCDATA_SKIP_FRAMESET 0x1
  /* If the FCDATA_FUNC_IS_DATA_GETTER bit is set, then the mFunc of the
     FrameConstructionData is a getter function that can be used to get the
     actual FrameConstructionData to use. */
#define FCDATA_FUNC_IS_DATA_GETTER 0x2
  /* If the FCDATA_FUNC_IS_FULL_CTOR bit is set, then the FrameConstructionData
     has an mFullConstructor.  In this case, there is no relevant mData or
     mFunc */
#define FCDATA_FUNC_IS_FULL_CTOR 0x4
  /* If FCDATA_DISALLOW_OUT_OF_FLOW is set, do not allow the frame to
     float or be absolutely positioned.  This can also be used with
     FCDATA_FUNC_IS_FULL_CTOR to indicate what the full-constructor
     function will do. */
#define FCDATA_DISALLOW_OUT_OF_FLOW 0x8
  /* If FCDATA_FORCE_NULL_ABSPOS_CONTAINER is set, make sure to push a
     null absolute containing block before processing children for this
     frame.  If this is not set, the frame will be pushed as the
     absolute containing block as needed, based on its style */
#define FCDATA_FORCE_NULL_ABSPOS_CONTAINER 0x10
  /* If FCDATA_WRAP_KIDS_IN_BLOCKS is set, the inline kids of the frame
     will be wrapped in blocks.  This is only usable for MathML at the
     moment. */
#define FCDATA_WRAP_KIDS_IN_BLOCKS 0x20
  /* If FCDATA_SUPPRESS_FRAME is set, no frame should be created for the
     content.  If this bit is set, nothing else in the struct needs to be
     set. */
#define FCDATA_SUPPRESS_FRAME 0x40
  /* If FCDATA_MAY_NEED_SCROLLFRAME is set, the new frame should be wrapped in
     a scrollframe if its overflow type so requires. */
#define FCDATA_MAY_NEED_SCROLLFRAME 0x80
#ifdef MOZ_XUL
  /* If FCDATA_IS_POPUP is set, the new frame is a XUL popup frame.  These need
     some really weird special handling.  */
#define FCDATA_IS_POPUP 0x100
#endif /* MOZ_XUL */
  /* If FCDATA_SKIP_ABSPOS_PUSH is set, don't push this frame as an
     absolute containing block, no matter what its style says. */
#define FCDATA_SKIP_ABSPOS_PUSH 0x200
  /* If FCDATA_DISALLOW_GENERATED_CONTENT is set, then don't allow generated
     content when processing kids of this frame.  This should not be used with
     FCDATA_FUNC_IS_FULL_CTOR */
#define FCDATA_DISALLOW_GENERATED_CONTENT 0x400
  /* If FCDATA_IS_TABLE_PART is set, then the frame is some sort of
     table-related thing and we should not attempt to fetch a table-cell parent
     for it if it's inside another table-related frame. */
#define FCDATA_IS_TABLE_PART 0x800
  /* If FCDATA_IS_INLINE is set, then the frame is a non-replaced CSS
     inline box. */
#define FCDATA_IS_INLINE 0x1000
  /* If FCDATA_IS_LINE_PARTICIPANT is set, the frame is something that will
     return true for IsFrameOfType(nsIFrame::eLineParticipant) */
#define FCDATA_IS_LINE_PARTICIPANT 0x2000
  /* If FCDATA_IS_LINE_BREAK is set, the frame is something that will
     induce a line break boundary before and after itself. */
#define FCDATA_IS_LINE_BREAK 0x4000
  /* If FCDATA_ALLOW_BLOCK_STYLES is set, allow block styles when processing
     children.  This should not be used with FCDATA_FUNC_IS_FULL_CTOR. */
#define FCDATA_ALLOW_BLOCK_STYLES 0x8000
  /* If FCDATA_USE_CHILD_ITEMS is set, then use the mChildItems in the relevant
     FrameConstructionItem instead of trying to process the content's children.
     This can be used with or without FCDATA_FUNC_IS_FULL_CTOR.
     The child items might still need table pseudo processing. */
#define FCDATA_USE_CHILD_ITEMS 0x10000
  /* If FCDATA_FORCED_NON_SCROLLABLE_BLOCK is set, then this block
     would have been scrollable but has been forced to be
     non-scrollable due to being in a paginated context. */
#define FCDATA_FORCED_NON_SCROLLABLE_BLOCK 0x20000
  /* If FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS is set, then create a
     block formatting context wrapper around the kids of this frame
     using the FrameConstructionData's mPseudoAtom for its anonymous
     box type. */
#define FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS 0x40000
  /* If FCDATA_IS_SVG_TEXT is set, then this text frame is a descendant of
     an SVG text frame. */
#define FCDATA_IS_SVG_TEXT 0x80000
  /**
   * display:contents
   */
#define FCDATA_IS_CONTENTS 0x100000
  /**
   * When FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS is set, this bit says
   * if we should create a grid/flex/columnset container instead of
   * a block wrapper when the styles says so.
   */
#define FCDATA_ALLOW_GRID_FLEX_COLUMNSET 0x200000

  /* Structure representing information about how a frame should be
     constructed.  */
  struct FrameConstructionData {
    // Flag bits that can modify the way the construction happens
    uint32_t mBits;
    // We have exactly one of three types of functions, so use a union for
    // better cache locality for the ones that aren't pointer-to-member.  That
    // one needs to be separate, because we can't cast between it and the
    // others and hence wouldn't be able to initialize the union without a
    // constructor and all the resulting generated code.  See documentation
    // above for FrameCreationFunc, FrameConstructionDataGetter, and
    // FrameFullConstructor to see what the functions would do.
    union Func {
      FrameCreationFunc mCreationFunc;
      FrameConstructionDataGetter mDataGetter;
    } mFunc;
    FrameFullConstructor mFullConstructor;
    // For cases when FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS is set, the
    // anonymous box type to use for that wrapper.
    nsICSSAnonBoxPseudo * const * const mAnonBoxPseudo;
  };

  /* Structure representing a mapping of an atom to a FrameConstructionData.
     This can be used with non-static atoms, assuming that the nsIAtom* is
     stored somewhere that this struct can point to (that is, a static
     nsIAtom*) and that it's allocated before the struct is ever used. */
  struct FrameConstructionDataByTag {
    // Pointer to nsIAtom* is used because we want to initialize this
    // statically, so before our atom tables are set up.
    const nsIAtom * const * const mTag;
    const FrameConstructionData mData;
  };

  /* Structure representing a mapping of an integer to a
     FrameConstructionData. There are no magic integer values here. */
  struct FrameConstructionDataByInt {
    /* Could be used for display or whatever else */
    const int32_t mInt;
    const FrameConstructionData mData;
  };

  struct FrameConstructionDataByDisplay {
#ifdef DEBUG
    const mozilla::StyleDisplay mDisplay;
#endif
    const FrameConstructionData mData;
  };

#ifdef DEBUG
#define FCDATA_FOR_DISPLAY(_display, _fcdata) \
  { _display, _fcdata }
#else
#define FCDATA_FOR_DISPLAY(_display, _fcdata) \
  { _fcdata }
#endif

  /* Structure that has a FrameConstructionData and style context pseudo-type
     for a table pseudo-frame */
  struct PseudoParentData {
    const FrameConstructionData mFCData;
    nsICSSAnonBoxPseudo * const * const mPseudoType;
  };
  /* Array of such structures that we use to properly construct table
     pseudo-frames as needed */
  static const PseudoParentData sPseudoParentData[eParentTypeCount];

  /* A function that takes an integer, content, style context, and array of
     FrameConstructionDataByInts and finds the appropriate frame construction
     data to use and returns it.  This can return null if none of the integers
     match or if the matching integer has a FrameConstructionDataGetter that
     returns null. */
  static const FrameConstructionData*
    FindDataByInt(int32_t aInt, Element* aElement,
                  nsStyleContext* aStyleContext,
                  const FrameConstructionDataByInt* aDataPtr,
                  uint32_t aDataLength);

  /* A function that takes a tag, content, style context, and array of
     FrameConstructionDataByTags and finds the appropriate frame construction
     data to use and returns it.  This can return null if none of the tags
     match or if the matching tag has a FrameConstructionDataGetter that
     returns null. */
  static const FrameConstructionData*
    FindDataByTag(nsIAtom* aTag, Element* aElement,
                  nsStyleContext* aStyleContext,
                  const FrameConstructionDataByTag* aDataPtr,
                  uint32_t aDataLength);

  /* A class representing a list of FrameConstructionItems */
  class FrameConstructionItemList final {
  public:
    FrameConstructionItemList() :
      mInlineCount(0),
      mBlockCount(0),
      mLineParticipantCount(0),
      mItemCount(0),
      mLineBoundaryAtStart(false),
      mLineBoundaryAtEnd(false),
      mParentHasNoXBLChildren(false),
      mTriedConstructingFrames(false)
    {
      memset(mDesiredParentCounts, 0, sizeof(mDesiredParentCounts));
    }

    ~FrameConstructionItemList() {
      while (FrameConstructionItem* item = mItems.popFirst()) {
        delete item;
      }

      // Create the undisplayed entries for our mUndisplayedItems, if any, but
      // only if we have tried constructing frames for this item list.  If we
      // haven't, then we're just throwing it away and will probably try again.
      if (!mUndisplayedItems.IsEmpty() && mTriedConstructingFrames) {
        // We could store the frame manager in a member, but just
        // getting it off the style context is not too bad.
        nsFrameManager *mgr =
          mUndisplayedItems[0].mStyleContext->PresContext()->FrameManager();
        for (uint32_t i = 0; i < mUndisplayedItems.Length(); ++i) {
          UndisplayedItem& item = mUndisplayedItems[i];
          mgr->SetUndisplayedContent(item.mContent, item.mStyleContext);
        }
      }
    }

    void SetLineBoundaryAtStart(bool aBoundary) { mLineBoundaryAtStart = aBoundary; }
    void SetLineBoundaryAtEnd(bool aBoundary) { mLineBoundaryAtEnd = aBoundary; }
    void SetParentHasNoXBLChildren(bool aHasNoXBLChildren) {
      mParentHasNoXBLChildren = aHasNoXBLChildren;
    }
    void SetTriedConstructingFrames() { mTriedConstructingFrames = true; }
    bool HasLineBoundaryAtStart() { return mLineBoundaryAtStart; }
    bool HasLineBoundaryAtEnd() { return mLineBoundaryAtEnd; }
    bool ParentHasNoXBLChildren() { return mParentHasNoXBLChildren; }
    bool IsEmpty() const { return mItems.isEmpty(); }
    bool AnyItemsNeedBlockParent() const { return mLineParticipantCount != 0; }
    bool AreAllItemsInline() const { return mInlineCount == mItemCount; }
    bool AreAllItemsBlock() const { return mBlockCount == mItemCount; }
    bool AllWantParentType(ParentType aDesiredParentType) const {
      return mDesiredParentCounts[aDesiredParentType] == mItemCount;
    }

    // aSuppressWhiteSpaceOptimizations is true if optimizations that
    // skip constructing whitespace frames for this item or items
    // around it cannot be performed.
    // Also, the return value is always non-null, thanks to infallible 'new'.
    FrameConstructionItem* AppendItem(const FrameConstructionData* aFCData,
                                      nsIContent* aContent,
                                      nsIAtom* aTag,
                                      int32_t aNameSpaceID,
                                      PendingBinding* aPendingBinding,
                                      already_AddRefed<nsStyleContext>&& aStyleContext,
                                      bool aSuppressWhiteSpaceOptimizations,
                                      nsTArray<nsIAnonymousContentCreator::ContentInfo>* aAnonChildren)
    {
      FrameConstructionItem* item =
        new FrameConstructionItem(aFCData, aContent, aTag, aNameSpaceID,
                                  aPendingBinding, aStyleContext,
                                  aSuppressWhiteSpaceOptimizations,
                                  aAnonChildren);
      mItems.insertBack(item);
      ++mItemCount;
      ++mDesiredParentCounts[item->DesiredParentType()];
      return item;
    }

    // Arguments are the same as AppendItem().
    FrameConstructionItem* PrependItem(const FrameConstructionData* aFCData,
                                       nsIContent* aContent,
                                       nsIAtom* aTag,
                                       int32_t aNameSpaceID,
                                       PendingBinding* aPendingBinding,
                                       already_AddRefed<nsStyleContext>&& aStyleContext,
                                       bool aSuppressWhiteSpaceOptimizations,
                                       nsTArray<nsIAnonymousContentCreator::ContentInfo>* aAnonChildren)
    {
      FrameConstructionItem* item =
        new FrameConstructionItem(aFCData, aContent, aTag, aNameSpaceID,
                                  aPendingBinding, aStyleContext,
                                  aSuppressWhiteSpaceOptimizations,
                                  aAnonChildren);
      mItems.insertFront(item);
      ++mItemCount;
      ++mDesiredParentCounts[item->DesiredParentType()];
      return item;
    }

    void AppendUndisplayedItem(nsIContent* aContent,
                               nsStyleContext* aStyleContext) {
      mUndisplayedItems.AppendElement(UndisplayedItem(aContent, aStyleContext));
    }

    void InlineItemAdded() { ++mInlineCount; }
    void BlockItemAdded() { ++mBlockCount; }
    void LineParticipantItemAdded() { ++mLineParticipantCount; }

    class Iterator {
    public:
      explicit Iterator(FrameConstructionItemList& aList)
        : mCurrent(aList.mItems.getFirst())
        , mList(aList)
      {}
      Iterator(const Iterator& aOther) :
        mCurrent(aOther.mCurrent),
        mList(aOther.mList)
      {}

      bool operator==(const Iterator& aOther) const {
        MOZ_ASSERT(&mList == &aOther.mList, "Iterators for different lists?");
        return mCurrent == aOther.mCurrent;
      }
      bool operator!=(const Iterator& aOther) const {
        return !(*this == aOther);
      }
      Iterator& operator=(const Iterator& aOther) {
        MOZ_ASSERT(&mList == &aOther.mList, "Iterators for different lists?");
        mCurrent = aOther.mCurrent;
        return *this;
      }

      FrameConstructionItemList* List() {
        return &mList;
      }

      FrameConstructionItem& item() {
        MOZ_ASSERT(!IsDone(), "Should have checked IsDone()!");
        return *mCurrent;
      }

      const FrameConstructionItem& item() const {
        MOZ_ASSERT(!IsDone(), "Should have checked IsDone()!");
        return *mCurrent;
      }

      bool IsDone() const { return mCurrent == nullptr; }
      bool AtStart() const { return mCurrent == mList.mItems.getFirst(); }
      void Next() {
        NS_ASSERTION(!IsDone(), "Should have checked IsDone()!");
        mCurrent = mCurrent->getNext();
      }
      void Prev() {
        NS_ASSERTION(!AtStart(), "Should have checked AtStart()!");
        mCurrent = mCurrent ? mCurrent->getPrevious() : mList.mItems.getLast();
      }
      void SetToEnd() { mCurrent = nullptr; }

      // Skip over all items that want the given parent type. Return whether
      // the iterator is done after doing that.  The iterator must not be done
      // when this is called.
      inline bool SkipItemsWantingParentType(ParentType aParentType);

      // Skip over all items that want a parent type different from the given
      // one.  Return whether the iterator is done after doing that.  The
      // iterator must not be done when this is called.
      inline bool SkipItemsNotWantingParentType(ParentType aParentType);

      // Skip over non-replaced inline frames and positioned frames.
      // Return whether the iterator is done after doing that.
      // The iterator must not be done when this is called.
      inline bool SkipItemsThatNeedAnonFlexOrGridItem(
        const nsFrameConstructorState& aState,
        bool aIsWebkitBox);

      // Skip to the first frame that is a non-replaced inline or is
      // positioned.  Return whether the iterator is done after doing that.
      // The iterator must not be done when this is called.
      inline bool SkipItemsThatDontNeedAnonFlexOrGridItem(
        const nsFrameConstructorState& aState,
        bool aIsWebkitBox);

      // Skip over all items that do not want a ruby parent.  Return whether
      // the iterator is done after doing that.  The iterator must not be done
      // when this is called.
      inline bool SkipItemsNotWantingRubyParent();

      // Skip over whitespace.  Return whether the iterator is done after doing
      // that.  The iterator must not be done, and must be pointing to a
      // whitespace item when this is called.
      inline bool SkipWhitespace(nsFrameConstructorState& aState);

      // Remove the item pointed to by this iterator from its current list and
      // Append it to aTargetList.  This iterator is advanced to point to the
      // next item in its list.  aIter must not be done.  aTargetList must not be
      // the list this iterator is iterating over..
      void AppendItemToList(FrameConstructionItemList& aTargetList);

      // As above, but moves all items starting with this iterator until we
      // get to aEnd; the item pointed to by aEnd is not stolen.  This method
      // might have optimizations over just looping and doing StealItem for
      // some special cases.  After this method returns, this iterator will
      // point to the item aEnd points to now; aEnd is not modified.
      // aTargetList must not be the list this iterator is iterating over.
      void AppendItemsToList(const Iterator& aEnd,
                             FrameConstructionItemList& aTargetList);

      // Insert aItem in this iterator's list right before the item pointed to
      // by this iterator.  After the insertion, this iterator will continue to
      // point to the item it now points to (the one just after the
      // newly-inserted item).  This iterator is allowed to be done; in that
      // case this call just appends the given item to the list.
      void InsertItem(FrameConstructionItem* aItem);

      // Delete the items between this iterator and aEnd, including the item
      // this iterator currently points to but not including the item pointed
      // to by aEnd.  When this returns, this iterator will point to the same
      // item as aEnd.  This iterator must not equal aEnd when this method is
      // called.
      void DeleteItemsTo(const Iterator& aEnd);

    private:
      FrameConstructionItem* mCurrent;
      FrameConstructionItemList& mList;
    };

  private:
    struct UndisplayedItem {
      UndisplayedItem(nsIContent* aContent, nsStyleContext* aStyleContext) :
        mContent(aContent), mStyleContext(aStyleContext)
      {}

      nsIContent * const mContent;
      RefPtr<nsStyleContext> mStyleContext;
    };

    // Adjust our various counts for aItem being added or removed.  aDelta
    // should be either +1 or -1 depending on which is happening.
    void AdjustCountsForItem(FrameConstructionItem* aItem, int32_t aDelta);

    mozilla::LinkedList<FrameConstructionItem> mItems;
    uint32_t mInlineCount;
    uint32_t mBlockCount;
    uint32_t mLineParticipantCount;
    uint32_t mItemCount;
    uint32_t mDesiredParentCounts[eParentTypeCount];
    // True if there is guaranteed to be a line boundary before the
    // frames created by these items
    bool mLineBoundaryAtStart;
    // True if there is guaranteed to be a line boundary after the
    // frames created by these items
    bool mLineBoundaryAtEnd;
    // True if the parent is guaranteed to have no XBL anonymous children
    bool mParentHasNoXBLChildren;
    // True if we have tried constructing frames from this list
    bool mTriedConstructingFrames;

    nsTArray<UndisplayedItem> mUndisplayedItems;
  };

  typedef FrameConstructionItemList::Iterator FCItemIterator;

  /* A struct representing an item for which frames might need to be
   * constructed.  This contains all the information needed to construct the
   * frame other than the parent frame and whatever would be stored in the
   * frame constructor state. */
  struct FrameConstructionItem final
    : public mozilla::LinkedListElement<FrameConstructionItem> {
    FrameConstructionItem(const FrameConstructionData* aFCData,
                          nsIContent* aContent,
                          nsIAtom* aTag,
                          int32_t aNameSpaceID,
                          PendingBinding* aPendingBinding,
                          already_AddRefed<nsStyleContext>& aStyleContext,
                          bool aSuppressWhiteSpaceOptimizations,
                          nsTArray<nsIAnonymousContentCreator::ContentInfo>* aAnonChildren) :
      mFCData(aFCData), mContent(aContent), mTag(aTag),
      mPendingBinding(aPendingBinding), mStyleContext(aStyleContext),
      mNameSpaceID(aNameSpaceID),
      mSuppressWhiteSpaceOptimizations(aSuppressWhiteSpaceOptimizations),
      mIsText(false), mIsGeneratedContent(false),
      mIsAnonymousContentCreatorContent(false),
      mIsRootPopupgroup(false), mIsAllInline(false), mIsBlock(false),
      mHasInlineEnds(false), mIsPopup(false),
      mIsLineParticipant(false), mIsForSVGAElement(false)
    {
      if (aAnonChildren) {
        NS_ASSERTION(!(mFCData->mBits & FCDATA_FUNC_IS_FULL_CTOR) ||
                     mFCData->mFullConstructor ==
                       &nsCSSFrameConstructor::ConstructInline,
                     "This is going to fail");
        NS_ASSERTION(!(mFCData->mBits & FCDATA_USE_CHILD_ITEMS),
                     "nsIAnonymousContentCreator::CreateAnonymousContent "
                     "implementations should not output a list where the "
                     "items have children in this case");
        mAnonChildren.SwapElements(*aAnonChildren);
      }
    }
    ~FrameConstructionItem() {
      if (mIsGeneratedContent) {
        mContent->UnbindFromTree();
        NS_RELEASE(mContent);
      }
    }

    ParentType DesiredParentType() {
      return FCDATA_DESIRED_PARENT_TYPE(mFCData->mBits);
    }

    // Indicates whether (when in a flex or grid container) this item needs
    // to be wrapped in an anonymous block.  (Note that we implement
    // -webkit-box/-webkit-inline-box using our standard flexbox frame class,
    // but we use different rules for what gets wrapped. The aIsWebkitBox
    // parameter here tells us whether to use those different rules.)
    bool NeedsAnonFlexOrGridItem(const nsFrameConstructorState& aState,
                                 bool aIsWebkitBox);

    // Don't call this unless the frametree really depends on the answer!
    // Especially so for generated content, where we don't want to reframe
    // things.
    bool IsWhitespace(nsFrameConstructorState& aState) const;

    bool IsLineBoundary() const {
      return mIsBlock || (mFCData->mBits & FCDATA_IS_LINE_BREAK);
    }

    // Child frame construction items.
    FrameConstructionItemList mChildItems;

    // ContentInfo list for children that have yet to have
    // FrameConstructionItem objects created for them. This exists because
    // AddFrameConstructionItemsInternal needs a valid frame, but in the case
    // that nsIAnonymousContentCreator::CreateAnonymousContent returns items
    // that have their own children (so we have a tree of ContentInfo objects
    // rather than a flat list) we don't yet have a frame to provide to
    // AddFrameConstructionItemsInternal in order to create the items for the
    // grandchildren. That prevents FrameConstructionItems from being created
    // for these grandchildren (and any descendants that they may have),
    // otherwise they could have been added to the mChildItems member of their
    // parent FrameConstructionItem. As it is, the grandchildren ContentInfo
    // list has to be stored in this mAnonChildren member in order to delay
    // construction of the FrameConstructionItems for the grandchildren until
    // a frame has been created for their parent item.
    nsTArray<nsIAnonymousContentCreator::ContentInfo> mAnonChildren;

    // The FrameConstructionData to use.
    const FrameConstructionData* mFCData;
    // The nsIContent node to use when initializing the new frame.
    nsIContent* mContent;
    // The XBL-resolved tag name to use for frame construction.
    nsIAtom* mTag;
    // The PendingBinding for this frame construction item, if any.  May be
    // null.  We maintain a list of PendingBindings in the frame construction
    // state in the order in which AddToAttachedQueue should be called on them:
    // depth-first, post-order traversal order.  Since we actually traverse the
    // DOM in a mix of breadth-first and depth-first, it is the responsibility
    // of whoever constructs FrameConstructionItem kids of a given
    // FrameConstructionItem to push its mPendingBinding as the current
    // insertion point before doing so and pop it afterward.
    PendingBinding* mPendingBinding;
    // The style context to use for creating the new frame.
    RefPtr<nsStyleContext> mStyleContext;
    // The XBL-resolved namespace to use for frame construction.
    int32_t mNameSpaceID;
    // Whether optimizations to skip constructing textframes around
    // this content need to be suppressed.
    bool mSuppressWhiteSpaceOptimizations:1;
    // Whether this is a text content item.
    bool mIsText:1;
    // Whether this is a generated content container.
    // If it is, mContent is a strong pointer.
    bool mIsGeneratedContent:1;
    // Whether this is an item for nsIAnonymousContentCreator content.
    bool mIsAnonymousContentCreatorContent:1;
    // Whether this is an item for the root popupgroup.
    bool mIsRootPopupgroup:1;
    // Whether construction from this item will create only frames that are
    // IsInlineOutside() in the principal child list.  This is not precise, but
    // conservative: if true the frames will really be inline, whereas if false
    // they might still all be inline.
    bool mIsAllInline:1;
    // Whether construction from this item will create only frames that are
    // IsBlockOutside() in the principal child list.  This is not precise, but
    // conservative: if true the frames will really be blocks, whereas if false
    // they might still be blocks (and in particular, out-of-flows that didn't
    // find a containing block).
    bool mIsBlock:1;
    // Whether construction from this item will give leading and trailing
    // inline frames.  This is equal to mIsAllInline, except for inline frame
    // items, where it's always true, whereas mIsAllInline might be false due
    // to {ib} splits.
    bool mHasInlineEnds:1;
    // Whether construction from this item will create a popup that needs to
    // go into the global popup items.
    bool mIsPopup:1;
    // Whether this item should be treated as a line participant
    bool mIsLineParticipant:1;
    // Whether this item is for an SVG <a> element
    bool mIsForSVGAElement:1;

  private:
    FrameConstructionItem(const FrameConstructionItem& aOther) = delete; /* not implemented */
  };

  /**
   * Function to create the anonymous flex or grid items that we need.
   * If aParentFrame is not a nsFlexContainerFrame or nsGridContainerFrame then
   * this method is a NOP.
   * @param aItems the child frame construction items before pseudo creation
   * @param aParentFrame the parent frame
   */
  void CreateNeededAnonFlexOrGridItems(nsFrameConstructorState& aState,
                                       FrameConstructionItemList& aItems,
                                       nsIFrame* aParentFrame);

  enum RubyWhitespaceType
  {
    eRubyNotWhitespace,
    eRubyInterLevelWhitespace,
    // Includes inter-base and inter-annotation whitespace
    eRubyInterLeafWhitespace,
    eRubyInterSegmentWhitespace
  };

  /**
   * Function to compute the whitespace type according to the display
   * values of the previous and the next elements.
   */
  static inline RubyWhitespaceType ComputeRubyWhitespaceType(
    mozilla::StyleDisplay aPrevDisplay, mozilla::StyleDisplay aNextDisplay);

  /**
   * Function to interpret the type of whitespace between
   * |aStartIter| and |aEndIter|.
   */
  static inline RubyWhitespaceType InterpretRubyWhitespace(
    nsFrameConstructorState& aState,
    const FCItemIterator& aStartIter, const FCItemIterator& aEndIter);

  /**
   * Function to wrap consecutive misparented inline content into
   * a ruby base box or a ruby text box.
   */
  void WrapItemsInPseudoRubyLeafBox(FCItemIterator& aIter,
                                    nsStyleContext* aParentStyle,
                                    nsIContent* aParentContent);

  /**
   * Function to wrap consecutive misparented items
   * into a ruby level container.
   */
  inline void WrapItemsInPseudoRubyLevelContainer(
    nsFrameConstructorState& aState, FCItemIterator& aIter,
    nsStyleContext* aParentStyle, nsIContent* aParentContent);

  /**
   * Function to trim leading and trailing whitespaces.
   */
  inline void TrimLeadingAndTrailingWhitespaces(
    nsFrameConstructorState& aState, FrameConstructionItemList& aItems);

  /**
   * Function to create internal ruby boxes.
   */
  inline void CreateNeededPseudoInternalRubyBoxes(
    nsFrameConstructorState& aState,
    FrameConstructionItemList& aItems, nsIFrame* aParentFrame);

  /**
   * Function to create the pseudo intermediate containers we need.
   * @param aItems the child frame construction items before pseudo creation
   * @param aParentFrame the parent frame we're creating pseudos for
   */
  inline void CreateNeededPseudoContainers(nsFrameConstructorState& aState,
                                           FrameConstructionItemList& aItems,
                                           nsIFrame* aParentFrame);

  /**
   * Function to wrap consecutive items into a pseudo parent.
   */
  inline void WrapItemsInPseudoParent(nsIContent* aParentContent,
                                      nsStyleContext* aParentStyle,
                                      ParentType aWrapperType,
                                      FCItemIterator& aIter,
                                      const FCItemIterator& aEndIter);

  /**
   * Function to create the pseudo siblings we need.
   */
  inline void CreateNeededPseudoSiblings(nsFrameConstructorState& aState,
                                         FrameConstructionItemList& aItems,
                                         nsIFrame* aParentFrame);

  /**
   * Function to adjust aParentFrame to deal with captions.
   * @param aParentFrame the frame we think should be the parent.  This will be
   *        adjusted to point to the right parent frame.
   * @param aFCData the FrameConstructionData that would be used for frame
   *        construction.
   * @param aStyleContext the style context for aChildContent
   */
  // XXXbz this function should really go away once we rework pseudo-frame
  // handling to be better. This should simply be part of the job of
  // GetGeometricParent, and stuff like the frameitems and parent frame should
  // be kept track of in the state...
  void AdjustParentFrame(nsContainerFrame**           aParentFrame,
                         const FrameConstructionData* aFCData,
                         nsStyleContext*              aStyleContext);

  // END TABLE SECTION

protected:
  static nsIFrame* CreatePlaceholderFrameFor(nsIPresShell*     aPresShell,
                                             nsIContent*       aContent,
                                             nsIFrame*         aFrame,
                                             nsStyleContext*   aParentStyle,
                                             nsContainerFrame* aParentFrame,
                                             nsIFrame*         aPrevInFlow,
                                             nsFrameState      aTypeBit);

  static nsIFrame* CreateBackdropFrameFor(nsIPresShell* aPresShell,
                                          nsIContent* aContent,
                                          nsIFrame* aFrame,
                                          nsContainerFrame* aParentFrame);

private:
  // ConstructSelectFrame puts the new frame in aFrameItems and
  // handles the kids of the select.
  nsIFrame* ConstructSelectFrame(nsFrameConstructorState& aState,
                                 FrameConstructionItem&   aItem,
                                 nsContainerFrame*        aParentFrame,
                                 const nsStyleDisplay*    aStyleDisplay,
                                 nsFrameItems&            aFrameItems);

  // ConstructFieldSetFrame puts the new frame in aFrameItems and
  // handles the kids of the fieldset
  nsIFrame* ConstructFieldSetFrame(nsFrameConstructorState& aState,
                                   FrameConstructionItem&   aItem,
                                   nsContainerFrame*        aParentFrame,
                                   const nsStyleDisplay*    aStyleDisplay,
                                   nsFrameItems&            aFrameItems);

  // ConstructDetailsFrame puts the new frame in aFrameItems and
  // handles the kids of the details.
  nsIFrame* ConstructDetailsFrame(nsFrameConstructorState& aState,
                                  FrameConstructionItem& aItem,
                                  nsContainerFrame* aParentFrame,
                                  const nsStyleDisplay* aStyleDisplay,
                                  nsFrameItems& aFrameItems);

  // aParentFrame might be null.  If it is, that means it was an
  // inline frame.
  static const FrameConstructionData* FindTextData(nsIFrame* aParentFrame);

  void ConstructTextFrame(const FrameConstructionData* aData,
                          nsFrameConstructorState& aState,
                          nsIContent*              aContent,
                          nsContainerFrame*        aParentFrame,
                          nsStyleContext*          aStyleContext,
                          nsFrameItems&            aFrameItems);

  // If aPossibleTextContent is a text node and doesn't have a frame, append a
  // frame construction item for it to aItems.
  void AddTextItemIfNeeded(nsFrameConstructorState& aState,
                           const InsertionPoint& aInsertion,
                           nsIContent* aPossibleTextContent,
                           FrameConstructionItemList& aItems);

  // If aParentContent's child aContent is a text node and
  // doesn't have a frame, try to create a frame for it.
  void ReframeTextIfNeeded(nsIContent* aParentContent,
                           nsIContent* aContent);

  void AddPageBreakItem(nsIContent* aContent,
                        nsStyleContext* aMainStyleContext,
                        FrameConstructionItemList& aItems);

  // Function to find FrameConstructionData for aElement.  Will return
  // null if aElement is not HTML.
  // aParentFrame might be null.  If it is, that means it was an
  // inline frame.
  static const FrameConstructionData* FindHTMLData(Element* aContent,
                                                   nsIAtom* aTag,
                                                   int32_t aNameSpaceID,
                                                   nsIFrame* aParentFrame,
                                                   nsStyleContext* aStyleContext);
  // HTML data-finding helper functions
  static const FrameConstructionData*
    FindImgData(Element* aElement, nsStyleContext* aStyleContext);
  static const FrameConstructionData*
    FindImgControlData(Element* aElement, nsStyleContext* aStyleContext);
  static const FrameConstructionData*
    FindInputData(Element* aElement, nsStyleContext* aStyleContext);
  static const FrameConstructionData*
    FindObjectData(Element* aElement, nsStyleContext* aStyleContext);
  static const FrameConstructionData*
    FindCanvasData(Element* aElement, nsStyleContext* aStyleContext);

  /* Construct a frame from the given FrameConstructionItem.  This function
     will handle adding the frame to frame lists, processing children, setting
     the frame as the primary frame for the item's content, and so forth.

     @param aItem the FrameConstructionItem to use.
     @param aState the frame construction state to use.
     @param aParentFrame the frame to set as the parent of the
                         newly-constructed frame.
     @param aFrameItems the frame list to add the new frame (or its
                        placeholder) to.
  */
  void ConstructFrameFromItemInternal(FrameConstructionItem& aItem,
                                      nsFrameConstructorState& aState,
                                      nsContainerFrame* aParentFrame,
                                      nsFrameItems& aFrameItems);

  // possible flags for AddFrameConstructionItemInternal's aFlags argument
  /* Allow xbl:base to affect the tag/namespace used. */
#define ITEM_ALLOW_XBL_BASE 0x1
  /* Allow page-break before and after items to be created if the
     style asks for them. */
#define ITEM_ALLOW_PAGE_BREAK 0x2
  /* The item is a generated content item. */
#define ITEM_IS_GENERATED_CONTENT 0x4
  /* The item is within an SVG text block frame. */
#define ITEM_IS_WITHIN_SVG_TEXT 0x8
  /* The item allows items to be created for SVG <textPath> children. */
#define ITEM_ALLOWS_TEXT_PATH_CHILD 0x10
  /* The item is content created by an nsIAnonymousContentCreator frame */
#define ITEM_IS_ANONYMOUSCONTENTCREATOR_CONTENT 0x20
  // The guts of AddFrameConstructionItems
  // aParentFrame might be null.  If it is, that means it was an
  // inline frame.
  void AddFrameConstructionItemsInternal(nsFrameConstructorState& aState,
                                         nsIContent*              aContent,
                                         nsContainerFrame*        aParentFrame,
                                         nsIAtom*                 aTag,
                                         int32_t                  aNameSpaceID,
                                         bool                     aSuppressWhiteSpaceOptimizations,
                                         nsStyleContext*          aStyleContext,
                                         uint32_t                 aFlags,
                                         nsTArray<nsIAnonymousContentCreator::ContentInfo>* aAnonChildren,
                                         FrameConstructionItemList& aItems);

  /**
   * Construct frames for the given item list and parent frame, and put the
   * resulting frames in aFrameItems.
   */
  void ConstructFramesFromItemList(nsFrameConstructorState& aState,
                                   FrameConstructionItemList& aItems,
                                   nsContainerFrame* aParentFrame,
                                   nsFrameItems& aFrameItems);
  void ConstructFramesFromItem(nsFrameConstructorState& aState,
                               FCItemIterator& aItem,
                               nsContainerFrame* aParentFrame,
                               nsFrameItems& aFrameItems);
  static bool AtLineBoundary(FCItemIterator& aIter);

  nsresult GetAnonymousContent(nsIContent* aParent,
                               nsIFrame* aParentFrame,
                               nsTArray<nsIAnonymousContentCreator::ContentInfo>& aAnonContent);

//MathML Mod - RBS
  /**
   * Takes the frames in aBlockItems and wraps them in a new anonymous block
   * frame whose content is aContent and whose parent will be aParentFrame.
   * The anonymous block is added to aNewItems and aBlockItems is cleared.
   */
  void FlushAccumulatedBlock(nsFrameConstructorState& aState,
                             nsIContent* aContent,
                             nsContainerFrame* aParentFrame,
                             nsFrameItems& aBlockItems,
                             nsFrameItems& aNewItems);

  // Function to find FrameConstructionData for aContent.  Will return
  // null if aContent is not MathML.
  static const FrameConstructionData* FindMathMLData(Element* aElement,
                                                     nsIAtom* aTag,
                                                     int32_t aNameSpaceID,
                                                     nsStyleContext* aStyleContext);

  // Function to find FrameConstructionData for aContent.  Will return
  // null if aContent is not XUL.
  static const FrameConstructionData* FindXULTagData(Element* aElement,
                                                     nsIAtom* aTag,
                                                     int32_t aNameSpaceID,
                                                     nsStyleContext* aStyleContext);
  // XUL data-finding helper functions and structures
#ifdef MOZ_XUL
  static const FrameConstructionData*
    FindPopupGroupData(Element* aElement, nsStyleContext* aStyleContext);
  // sXULTextBoxData used for both labels and descriptions
  static const FrameConstructionData sXULTextBoxData;
  static const FrameConstructionData*
    FindXULLabelData(Element* aElement, nsStyleContext* aStyleContext);
  static const FrameConstructionData*
    FindXULDescriptionData(Element* aElement, nsStyleContext* aStyleContext);
#ifdef XP_MACOSX
  static const FrameConstructionData*
    FindXULMenubarData(Element* aElement, nsStyleContext* aStyleContext);
#endif /* XP_MACOSX */
  static const FrameConstructionData*
    FindXULListBoxBodyData(Element* aElement, nsStyleContext* aStyleContext);
  static const FrameConstructionData*
    FindXULListItemData(Element* aElement, nsStyleContext* aStyleContext);
#endif /* MOZ_XUL */

  // Function to find FrameConstructionData for aContent using one of the XUL
  // display types.  Will return null if aDisplay doesn't have a XUL display
  // type.  This function performs no other checks, so should only be called if
  // we know for sure that the content is not something that should get a frame
  // constructed by tag.
  static const FrameConstructionData*
    FindXULDisplayData(const nsStyleDisplay* aDisplay,
                       Element* aElement,
                       nsStyleContext* aStyleContext);

  /**
   * Constructs an outer frame, an anonymous child that wraps its real
   * children, and its descendant frames.  This is used by both ConstructOuterSVG
   * and ConstructMarker, which both want an anonymous block child for their
   * children to go in to.
   */
  nsContainerFrame* ConstructFrameWithAnonymousChild(
                                  nsFrameConstructorState& aState,
                                  FrameConstructionItem&   aItem,
                                  nsContainerFrame*        aParentFrame,
                                  nsFrameItems&            aFrameItems,
                                  ContainerFrameCreationFunc aConstructor,
                                  ContainerFrameCreationFunc aInnerConstructor,
                                  nsICSSAnonBoxPseudo*     aInnerPseudo,
                                  bool                     aCandidateRootFrame);

  /**
   * Construct an nsSVGOuterSVGFrame.
   */
  nsIFrame* ConstructOuterSVG(nsFrameConstructorState& aState,
                              FrameConstructionItem&   aItem,
                              nsContainerFrame*        aParentFrame,
                              const nsStyleDisplay*    aDisplay,
                              nsFrameItems&            aFrameItems);

  /**
   * Construct an nsSVGMarkerFrame.
   */
  nsIFrame* ConstructMarker(nsFrameConstructorState& aState,
                            FrameConstructionItem&   aItem,
                            nsContainerFrame*        aParentFrame,
                            const nsStyleDisplay*    aDisplay,
                            nsFrameItems&            aFrameItems);

  static const FrameConstructionData* FindSVGData(Element* aElement,
                                                  nsIAtom* aTag,
                                                  int32_t aNameSpaceID,
                                                  nsIFrame* aParentFrame,
                                                  bool aIsWithinSVGText,
                                                  bool aAllowsTextPathChild,
                                                  nsStyleContext* aStyleContext);

  /* Not static because it does PropagateScrollToViewport.  If this
     changes, make this static */
  const FrameConstructionData*
    FindDisplayData(const nsStyleDisplay* aDisplay, Element* aElement,
                    nsStyleContext* aStyleContext);

  /**
   * Construct a scrollable block frame
   */
  nsIFrame* ConstructScrollableBlock(nsFrameConstructorState& aState,
                                     FrameConstructionItem&   aItem,
                                     nsContainerFrame*        aParentFrame,
                                     const nsStyleDisplay*    aDisplay,
                                     nsFrameItems&            aFrameItems);

  /**
   * Construct a scrollable block frame using the given block frame creation
   * function.
   */
  nsIFrame* ConstructScrollableBlockWithConstructor(
    nsFrameConstructorState& aState,
    FrameConstructionItem& aItem,
    nsContainerFrame* aParentFrame,
    const nsStyleDisplay* aDisplay,
    nsFrameItems& aFrameItems,
    BlockFrameCreationFunc aConstructor);

  /**
   * Construct a non-scrollable block frame
   */
  nsIFrame* ConstructNonScrollableBlock(nsFrameConstructorState& aState,
                                        FrameConstructionItem&   aItem,
                                        nsContainerFrame*        aParentFrame,
                                        const nsStyleDisplay*    aDisplay,
                                        nsFrameItems&            aFrameItems);

  /**
   * Construct a non-scrollable block frame using the given block frame creation
   * function.
   */
  nsIFrame* ConstructNonScrollableBlockWithConstructor(
    nsFrameConstructorState& aState,
    FrameConstructionItem& aItem,
    nsContainerFrame* aParentFrame,
    const nsStyleDisplay* aDisplay,
    nsFrameItems& aFrameItems,
    BlockFrameCreationFunc aConstructor);

  /**
   * This adds FrameConstructionItem objects to aItemsToConstruct for the
   * anonymous content returned by an nsIAnonymousContentCreator::
   * CreateAnonymousContent implementation.
   */
  void AddFCItemsForAnonymousContent(
            nsFrameConstructorState& aState,
            nsContainerFrame* aFrame,
            nsTArray<nsIAnonymousContentCreator::ContentInfo>& aAnonymousItems,
            FrameConstructionItemList& aItemsToConstruct,
            uint32_t aExtraFlags = 0);

  /**
   * Construct the frames for the children of aContent.  "children" is defined
   * as "whatever FlattenedChildIterator returns for aContent".  This means we're
   * basically operating on children in the "flattened tree" per sXBL/XBL2.
   * This method will also handle constructing ::before, ::after,
   * ::first-letter, and ::first-line frames, as needed and if allowed.
   *
   * If the parent is a float containing block, this method will handle pushing
   * it as the float containing block in aState (so there's no need for callers
   * to push it themselves).
   *
   * @param aState the frame construction state
   * @param aContent the content node whose children need frames
   * @param aStyleContext the style context for aContent
   * @param aParentFrame the frame to use as the parent frame for the new in-flow
   *        kids. Note that this must be its own content insertion frame, but
   *        need not be be the primary frame for aContent.  This frame will be
   *        pushed as the float containing block, as needed.  aFrame is also
   *        used to find the parent style context for the kids' style contexts
   *        (not necessary aFrame's style context).
   * @param aCanHaveGeneratedContent Whether to allow :before and
   *        :after styles on the parent.
   * @param aFrameItems the list in which we should place the in-flow children
   * @param aAllowBlockStyles Whether to allow first-letter and first-line
   *        styles on the parent.
   * @param aPendingBinding Make sure to push this into aState before doing any
   *        child item construction.
   * @param aPossiblyLeafFrame if non-null, this should be used for the isLeaf
   *        test and the anonymous content creation.  If null, aFrame will be
   *        used.
   */
  void ProcessChildren(nsFrameConstructorState& aState,
                       nsIContent*              aContent,
                       nsStyleContext*          aStyleContext,
                       nsContainerFrame*        aParentFrame,
                       const bool               aCanHaveGeneratedContent,
                       nsFrameItems&            aFrameItems,
                       const bool               aAllowBlockStyles,
                       PendingBinding*          aPendingBinding,
                       nsIFrame*                aPossiblyLeafFrame = nullptr);

  /**
   * These two functions are used when we start frame creation from a non-root
   * element. They should recreate the same state that we would have
   * arrived at if we had built frames from the root frame to aFrame.
   * Therefore, any calls to PushFloatContainingBlock and
   * PushAbsoluteContainingBlock during frame construction should get
   * corresponding logic in these functions.
   */
public:
  enum ContainingBlockType {
    ABS_POS,
    FIXED_POS
  };
  nsContainerFrame* GetAbsoluteContainingBlock(nsIFrame* aFrame,
                                               ContainingBlockType aType);
  nsContainerFrame* GetFloatContainingBlock(nsIFrame* aFrame);

private:
  // Build a scroll frame:
  //  Calls BeginBuildingScrollFrame, InitAndRestoreFrame, and then FinishBuildingScrollFrame.
  // @param aNewFrame the created scrollframe --- output only
  // @param aParentFrame the geometric parent that the scrollframe will have.
  void
  BuildScrollFrame(nsFrameConstructorState& aState,
                   nsIContent*              aContent,
                   nsStyleContext*          aContentStyle,
                   nsIFrame*                aScrolledFrame,
                   nsContainerFrame*        aParentFrame,
                   nsContainerFrame*&       aNewFrame);

  // Builds the initial ScrollFrame
  already_AddRefed<nsStyleContext>
  BeginBuildingScrollFrame(nsFrameConstructorState& aState,
                           nsIContent*              aContent,
                           nsStyleContext*          aContentStyle,
                           nsContainerFrame*        aParentFrame,
                           nsIAtom*                 aScrolledPseudo,
                           bool                     aIsRoot,
                           nsContainerFrame*&       aNewFrame);

  // Completes the building of the scrollframe:
  // Creates a view for the scrolledframe and makes it the child of the scrollframe.
  void
  FinishBuildingScrollFrame(nsContainerFrame* aScrollFrame,
                            nsIFrame* aScrolledFrame);

  // InitializeSelectFrame puts scrollFrame in aFrameItems if aBuildCombobox is false
  // aBuildCombobox indicates if we are building a combobox that has a dropdown
  // popup widget or not.
  nsresult
  InitializeSelectFrame(nsFrameConstructorState& aState,
                        nsContainerFrame*        aScrollFrame,
                        nsContainerFrame*        aScrolledFrame,
                        nsIContent*              aContent,
                        nsContainerFrame*        aParentFrame,
                        nsStyleContext*          aStyleContext,
                        bool                     aBuildCombobox,
                        PendingBinding*          aPendingBinding,
                        nsFrameItems&            aFrameItems);

  /**
   * ReResolve style for aElement then recreate frames if required.
   * Do nothing for other types of style changes, except for undisplayed nodes
   * (display:none/contents) which will have their style context updated in the
   * frame manager undisplayed maps.
   * @return null if frames were recreated, the new style context otherwise
   */
  nsStyleContext* MaybeRecreateFramesForElement(Element* aElement);

  /**
   * Recreate frames for aContent.
   * @param aContent the content to recreate frames for
   * @param aAsyncInsert if true then a restyle event will be posted to handle
   *   the required ContentInserted call instead of doing it immediately.
   * @param aFlags normally you want to pass REMOVE_FOR_RECONSTRUCTION here
   * @param aDestroyedFramesFor if non-null, it will contain the content that
   *   was actually reframed - it may be different than aContent.
   */
  nsresult
  RecreateFramesForContent(nsIContent*  aContent,
                           bool         aAsyncInsert,
                           RemoveFlags  aFlags,
                           nsIContent** aDestroyedFramesFor);

  // If removal of aFrame from the frame tree requires reconstruction of some
  // containing block (either of aFrame or of its parent) due to {ib} splits or
  // table pseudo-frames, recreate the relevant frame subtree.  The return value
  // indicates whether this happened.  If this method returns true, *aResult is
  // the return value of ReframeContainingBlock or RecreateFramesForContent.  If
  // this method returns false, the value of *aResult is not affected.  aFrame
  // and aResult must not be null.  aFrame must be the result of a
  // GetPrimaryFrame() call on a content node (which means its parent is also
  // not null).   If this method returns true, aDestroyedFramesFor contains the
  // content that was reframed.
  bool MaybeRecreateContainerForFrameRemoval(nsIFrame*    aFrame,
                                             RemoveFlags  aFlags,
                                             nsresult*    aResult,
                                             nsIContent** aDestroyedFramesFor);

  nsIFrame* CreateContinuingOuterTableFrame(nsIPresShell*     aPresShell,
                                            nsPresContext*    aPresContext,
                                            nsIFrame*         aFrame,
                                            nsContainerFrame* aParentFrame,
                                            nsIContent*       aContent,
                                            nsStyleContext*   aStyleContext);

  nsIFrame* CreateContinuingTableFrame(nsIPresShell*     aPresShell,
                                       nsIFrame*         aFrame,
                                       nsContainerFrame* aParentFrame,
                                       nsIContent*       aContent,
                                       nsStyleContext*   aStyleContext);

  //----------------------------------------

  // Methods support creating block frames and their children

  already_AddRefed<nsStyleContext>
  GetFirstLetterStyle(nsIContent*      aContent,
                      nsStyleContext*  aStyleContext);

  already_AddRefed<nsStyleContext>
  GetFirstLineStyle(nsIContent*      aContent,
                    nsStyleContext*  aStyleContext);

  bool ShouldHaveFirstLetterStyle(nsIContent*      aContent,
                                    nsStyleContext*  aStyleContext);

  // Check whether a given block has first-letter style.  Make sure to
  // only pass in blocks!  And don't pass in null either.
  bool HasFirstLetterStyle(nsIFrame* aBlockFrame);

  bool ShouldHaveFirstLineStyle(nsIContent*      aContent,
                                  nsStyleContext*  aStyleContext);

  void ShouldHaveSpecialBlockStyle(nsIContent*      aContent,
                                   nsStyleContext*  aStyleContext,
                                   bool*          aHaveFirstLetterStyle,
                                   bool*          aHaveFirstLineStyle);

  // |aContentParentFrame| should be null if it's really the same as
  // |aParentFrame|.
  // @param aFrameItems where we want to put the block in case it's in-flow.
  // @param aNewFrame an in/out parameter. On input it is the block to be
  // constructed. On output it is reset to the outermost
  // frame constructed (e.g. if we need to wrap the block in an
  // nsColumnSetFrame.
  // @param aParentFrame is the desired parent for the (possibly wrapped)
  // block
  // @param aContentParent is the parent the block would have if it
  // were in-flow
  // @param aPositionedFrameForAbsPosContainer if non-null, then the new
  // block should be an abs-pos container and aPositionedFrameForAbsPosContainer
  // is the frame whose style is making this block an abs-pos container.
  // @param aPendingBinding the pending binding  from this block's frame
  // construction item.
  void ConstructBlock(nsFrameConstructorState& aState,
                      nsIContent*              aContent,
                      nsContainerFrame*        aParentFrame,
                      nsContainerFrame*        aContentParentFrame,
                      nsStyleContext*          aStyleContext,
                      nsContainerFrame**       aNewFrame,
                      nsFrameItems&            aFrameItems,
                      nsIFrame*                aPositionedFrameForAbsPosContainer,
                      PendingBinding*          aPendingBinding);

  nsIFrame* ConstructInline(nsFrameConstructorState& aState,
                            FrameConstructionItem&   aItem,
                            nsContainerFrame*        aParentFrame,
                            const nsStyleDisplay*    aDisplay,
                            nsFrameItems&            aFrameItems);

  /**
   * Create any additional {ib} siblings needed to contain aChildItems and put
   * them in aSiblings.
   *
   * @param aState the frame constructor state
   * @param aInitialInline is an already-existing inline frame that will be
   *                       part of this {ib} split and come before everything
   *                       in aSiblings.
   * @param aIsPositioned true if aInitialInline is positioned.
   * @param aChildItems is a child list starting with a block; this method
   *                    assumes that the inline has already taken all the
   *                    children it wants.  When the method returns aChildItems
   *                    will be empty.
   * @param aSiblings the nsFrameItems to put the newly-created siblings into.
   *
   * This method is responsible for making any SetFrameIsIBSplit calls that are
   * needed.
   */
  void CreateIBSiblings(nsFrameConstructorState& aState,
                        nsContainerFrame* aInitialInline,
                        bool aIsPositioned,
                        nsFrameItems& aChildItems,
                        nsFrameItems& aSiblings);

  /**
   * For an inline aParentItem, construct its list of child
   * FrameConstructionItems and set its mIsAllInline flag appropriately.
   */
  void BuildInlineChildItems(nsFrameConstructorState& aState,
                             FrameConstructionItem& aParentItem,
                             bool aItemIsWithinSVGText,
                             bool aItemAllowsTextPathChild);

  // Determine whether we need to wipe out what we just did and start over
  // because we're doing something like adding block kids to an inline frame
  // (and therefore need an {ib} split).  aPrevSibling must be correct, even in
  // aIsAppend cases.  Passing aIsAppend false even when an append is happening
  // is ok in terms of correctness, but can lead to unnecessary reframing.  If
  // aIsAppend is true, then the caller MUST call
  // nsCSSFrameConstructor::AppendFramesToParent (as opposed to
  // nsFrameManager::InsertFrames directly) to add the new frames.
  // @return true if we reconstructed the containing block, false
  // otherwise
  bool WipeContainingBlock(nsFrameConstructorState& aState,
                             nsIFrame*                aContainingBlock,
                             nsIFrame*                aFrame,
                             FrameConstructionItemList& aItems,
                             bool                     aIsAppend,
                             nsIFrame*                aPrevSibling);

  nsresult ReframeContainingBlock(nsIFrame*    aFrame,
                                  RemoveFlags  aFlags,
                                  nsIContent** aReframeContent);

  //----------------------------------------

  // Methods support :first-letter style

  void CreateFloatingLetterFrame(nsFrameConstructorState& aState,
                                 nsIContent*              aTextContent,
                                 nsIFrame*                aTextFrame,
                                 nsContainerFrame*        aParentFrame,
                                 nsStyleContext*          aStyleContext,
                                 nsFrameItems&            aResult);

  void CreateLetterFrame(nsContainerFrame*        aBlockFrame,
                         nsContainerFrame*        aBlockContinuation,
                         nsIContent*              aTextContent,
                         nsContainerFrame*        aParentFrame,
                         nsFrameItems&            aResult);

  void WrapFramesInFirstLetterFrame(nsContainerFrame* aBlockFrame,
                                    nsFrameItems&     aBlockFrames);

  /**
   * Looks in the block aBlockFrame for a text frame that contains the
   * first-letter of the block and creates the necessary first-letter frames
   * and returns them in aLetterFrames.
   *
   * @param aBlockFrame the (first-continuation of) the block we are creating a
   *                    first-letter frame for
   * @param aBlockContinuation the current continuation of the block that we
   *                           are looking in for a textframe with suitable
   *                           contents for first-letter
   * @param aParentFrame the current frame whose children we are looking at for
   *                     a suitable first-letter textframe
   * @param aParentFrameList the first child of aParentFrame
   * @param aModifiedParent returns the parent of the textframe that contains
   *                        the first-letter
   * @param aTextFrame returns the textframe that had the first-letter
   * @param aPrevFrame returns the previous sibling of aTextFrame
   * @param aLetterFrames returns the frames that were created
   */
  void WrapFramesInFirstLetterFrame(nsContainerFrame*  aBlockFrame,
                                    nsContainerFrame*  aBlockContinuation,
                                    nsContainerFrame*  aParentFrame,
                                    nsIFrame*          aParentFrameList,
                                    nsContainerFrame** aModifiedParent,
                                    nsIFrame**         aTextFrame,
                                    nsIFrame**         aPrevFrame,
                                    nsFrameItems&      aLetterFrames,
                                    bool*              aStopLooking);

  void RecoverLetterFrames(nsContainerFrame* aBlockFrame);

  //
  nsresult RemoveLetterFrames(nsIPresShell*     aPresShell,
                              nsContainerFrame* aBlockFrame);

  // Recursive helper for RemoveLetterFrames
  nsresult RemoveFirstLetterFrames(nsIPresShell*     aPresShell,
                                   nsContainerFrame* aFrame,
                                   nsContainerFrame* aBlockFrame,
                                   bool*             aStopLooking);

  // Special remove method for those pesky floating first-letter frames
  nsresult RemoveFloatingFirstLetterFrames(nsIPresShell*    aPresShell,
                                           nsIFrame*        aBlockFrame);

  // Capture state for the frame tree rooted at the frame associated with the
  // content object, aContent
  void CaptureStateForFramesOf(nsIContent* aContent,
                               nsILayoutHistoryState* aHistoryState);

  //----------------------------------------

  // Methods support :first-line style

  // This method chops the initial inline-outside frames out of aFrameItems.
  // If aLineFrame is non-null, it appends them to that frame.  Otherwise, it
  // creates a new line frame, sets the inline frames as its initial child
  // list, and inserts that line frame at the front of what's left of
  // aFrameItems.  In both cases, the kids are reparented to the line frame.
  // After this call, aFrameItems holds the frames that need to become kids of
  // the block (possibly including line frames).
  void WrapFramesInFirstLineFrame(nsFrameConstructorState& aState,
                                  nsIContent*              aBlockContent,
                                  nsContainerFrame*        aBlockFrame,
                                  nsFirstLineFrame*        aLineFrame,
                                  nsFrameItems&            aFrameItems);

  // Handle the case when a block with first-line style is appended to (by
  // possibly calling WrapFramesInFirstLineFrame as needed).
  void AppendFirstLineFrames(nsFrameConstructorState& aState,
                             nsIContent*              aContent,
                             nsContainerFrame*        aBlockFrame,
                             nsFrameItems&            aFrameItems);

  nsresult InsertFirstLineFrames(nsFrameConstructorState& aState,
                                 nsIContent*              aContent,
                                 nsIFrame*                aBlockFrame,
                                 nsContainerFrame**       aParentFrame,
                                 nsIFrame*                aPrevSibling,
                                 nsFrameItems&            aFrameItems);

  /**
   * Find the right frame to use for aContent when looking for sibling
   * frames for aTargetContent.  If aPrevSibling is true, this
   * will look for last continuations, etc, as necessary.  This calls
   * IsValidSibling as needed; if that returns false it returns null.
   *
   * @param aContent the content to search for frames
   * @param aTargetContent the content we're finding a sibling frame for
   * @param aTargetContentDisplay the CSS display enum for aTargetContent if
   *          already known, UNSET_DISPLAY otherwise. It will be filled in
   *          if needed.
   * @param aParentFrame the nearest ancestor frame, used internally for
   *          finding ::after / ::before frames
   * @param aPrevSibling true if we're searching in reverse DOM order
   */
  nsIFrame* FindFrameForContentSibling(nsIContent* aContent,
                                       nsIContent* aTargetContent,
                                       mozilla::StyleDisplay& aTargetContentDisplay,
                                       nsContainerFrame* aParentFrame,
                                       bool aPrevSibling);

  /**
   * Find the frame for the content immediately preceding the one aIter
   * points to, following continuations if necessary.  aIter is passed by
   * value on purpose, so as not to modify the caller's iterator.
   *
   * @param aIter should be positioned such that aIter.GetPreviousChild()
   *          is the first content to search for frames
   * @param aTargetContent the content we're finding a sibling frame for
   * @param aTargetContentDisplay the CSS display enum for aTargetContent if
   *          already known, UNSET_DISPLAY otherwise. It will be filled in
   *          if needed.
   * @param aParentFrame the nearest ancestor frame, used inernally for
   *          finding ::after / ::before frames
   */
  nsIFrame* FindPreviousSibling(mozilla::dom::FlattenedChildIterator aIter,
                                nsIContent* aTargetContent,
                                mozilla::StyleDisplay& aTargetContentDisplay,
                                nsContainerFrame* aParentFrame);

  /**
   * Find the frame for the content node immediately following the one aIter
   * points to, following continuations if necessary.  aIter is passed by value
   * on purpose, so as not to modify the caller's iterator.
   *
   * @param aIter should be positioned such that aIter.GetNextChild()
   *          is the first content to search for frames
   * @param aTargetContent the content we're finding a sibling frame for
   * @param aTargetContentDisplay the CSS display enum for aTargetContent if
   *          already known, UNSET_DISPLAY otherwise. It will be filled in
   *          if needed.
   * @param aParentFrame the nearest ancestor frame, used inernally for
   *          finding ::after / ::before frames
   */
  nsIFrame* FindNextSibling(mozilla::dom::FlattenedChildIterator aIter,
                            nsIContent* aTargetContent,
                            mozilla::StyleDisplay& aTargetContentDisplay,
                            nsContainerFrame* aParentFrame);

  // Find the right previous sibling for an insertion.  This also updates the
  // parent frame to point to the correct continuation of the parent frame to
  // use, and returns whether this insertion is to be treated as an append.
  // aChild is the child being inserted.
  // aIsRangeInsertSafe returns whether it is safe to do a range insert with
  // aChild being the first child in the range. It is the callers'
  // responsibility to check whether a range insert is safe with regards to
  // fieldsets.
  // The skip parameters are used to ignore a range of children when looking
  // for a sibling. All nodes starting from aStartSkipChild and up to but not
  // including aEndSkipChild will be skipped over when looking for sibling
  // frames. Skipping a range can deal with XBL but not when there are multiple
  // insertion points.
  nsIFrame* GetInsertionPrevSibling(InsertionPoint* aInsertion, // inout
                                    nsIContent* aChild,
                                    bool* aIsAppend,
                                    bool* aIsRangeInsertSafe,
                                    nsIContent* aStartSkipChild = nullptr,
                                    nsIContent *aEndSkipChild = nullptr);

  /**
   * Return the insertion frame of the primary frame of aContent, or its nearest
   * ancestor that isn't display:contents.
   */
  nsContainerFrame* GetContentInsertionFrameFor(nsIContent* aContent);

  // see if aContent and aSibling are legitimate siblings due to restrictions
  // imposed by table columns
  // XXXbz this code is generally wrong, since the frame for aContent
  // may be constructed based on tag, not based on aDisplay!
  bool IsValidSibling(nsIFrame*              aSibling,
                      nsIContent*            aContent,
                      mozilla::StyleDisplay& aDisplay);

  void QuotesDirty() {
    NS_PRECONDITION(mUpdateCount != 0, "Instant quote updates are bad news");
    mQuotesDirty = true;
    mDocument->SetNeedLayoutFlush();
  }

  void CountersDirty() {
    NS_PRECONDITION(mUpdateCount != 0, "Instant counter updates are bad news");
    mCountersDirty = true;
    mDocument->SetNeedLayoutFlush();
  }

  /**
   * Add the pair (aContent, aStyleContext) to the undisplayed items
   * in aList as needed.  This method enforces the invariant that all
   * style contexts in the undisplayed content map must be non-pseudo
   * contexts and also handles unbinding undisplayed generated content
   * as needed.
   */
  void SetAsUndisplayedContent(nsFrameConstructorState& aState,
                               FrameConstructionItemList& aList,
                               nsIContent* aContent,
                               nsStyleContext* aStyleContext,
                               bool aIsGeneratedContent);
  // Create touch caret frame.
  void ConstructAnonymousContentForCanvas(nsFrameConstructorState& aState,
                                          nsIFrame* aFrame,
                                          nsIContent* aDocElement);

public:

  friend class nsFrameConstructorState;

private:

  nsIDocument*        mDocument;  // Weak ref

  // See the comment at the start of ConstructRootFrame for more details
  // about the following frames.

  // This is just the outermost frame for the root element.
  nsContainerFrame*   mRootElementFrame;
  // This is the frame for the root element that has no pseudo-element style.
  nsIFrame*           mRootElementStyleFrame;
  // This is the containing block that contains the root element ---
  // the real "initial containing block" according to CSS 2.1.
  nsContainerFrame*   mDocElementContainingBlock;
  nsIFrame*           mGfxScrollFrame;
  nsIFrame*           mPageSequenceFrame;
  nsQuoteList         mQuoteList;
  nsCounterManager    mCounterManager;
  // Current ProcessChildren depth.
  uint16_t            mCurrentDepth;
#ifdef DEBUG
  uint16_t            mUpdateCount;
#endif
  bool                mQuotesDirty : 1;
  bool                mCountersDirty : 1;
  bool                mIsDestroyingFrameTree : 1;
  // This is true if mDocElementContainingBlock supports absolute positioning
  bool                mHasRootAbsPosContainingBlock : 1;
  bool                mAlwaysCreateFramesForIgnorableWhitespace : 1;

  nsCOMPtr<nsILayoutHistoryState> mTempFrameTreeState;
};

#endif /* nsCSSFrameConstructor_h___ */