layout/generic/nsInlineFrame.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* rendering object for CSS display:inline objects */
   8
   9 #include "nsInlineFrame.h"
  10
  11 #include "gfxContext.h"
  12 #include "mozilla/ComputedStyle.h"
  13 #include "mozilla/Likely.h"
  14 #include "mozilla/PresShell.h"
  15 #include "mozilla/RestyleManager.h"
  16 #include "mozilla/ServoStyleSet.h"
  17 #include "mozilla/SVGTextFrame.h"
  18 #include "nsLineLayout.h"
  19 #include "nsBlockFrame.h"
  20 #include "nsLayoutUtils.h"
  21 #include "nsPlaceholderFrame.h"
  22 #include "nsGkAtoms.h"
  23 #include "nsPresContext.h"
  24 #include "nsPresContextInlines.h"
  25 #include "nsCSSAnonBoxes.h"
  26 #include "nsDisplayList.h"
  27 #include "nsStyleChangeList.h"
  28
  29 #ifdef DEBUG
  30 #  undef NOISY_PUSHING
  31 #endif
  32
  33 using namespace mozilla;
  34 using namespace mozilla::layout;
  35
  36 //////////////////////////////////////////////////////////////////////
  37
  38 // Basic nsInlineFrame methods
  39
  40 nsInlineFrame* NS_NewInlineFrame(PresShell* aPresShell, ComputedStyle* aStyle) {
  41   return new (aPresShell) nsInlineFrame(aStyle, aPresShell->GetPresContext());
  42 }
  43
  44 NS_IMPL_FRAMEARENA_HELPERS(nsInlineFrame)
  45
  46 NS_QUERYFRAME_HEAD(nsInlineFrame)
  47   NS_QUERYFRAME_ENTRY(nsInlineFrame)
  48 NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
  49
  50 #ifdef DEBUG_FRAME_DUMP
  51 nsresult nsInlineFrame::GetFrameName(nsAString& aResult) const {
  52   return MakeFrameName(u"Inline"_ns, aResult);
  53 }
  54 #endif
  55
  56 void nsInlineFrame::InvalidateFrame(uint32_t aDisplayItemKey,
  57                                     bool aRebuildDisplayItems) {
  58   if (IsInSVGTextSubtree()) {
  59     nsIFrame* svgTextFrame = nsLayoutUtils::GetClosestFrameOfType(
  60         GetParent(), LayoutFrameType::SVGText);
  61     svgTextFrame->InvalidateFrame();
  62     return;
  63   }
  64   nsContainerFrame::InvalidateFrame(aDisplayItemKey, aRebuildDisplayItems);
  65 }
  66
  67 void nsInlineFrame::InvalidateFrameWithRect(const nsRect& aRect,
  68                                             uint32_t aDisplayItemKey,
  69                                             bool aRebuildDisplayItems) {
  70   if (IsInSVGTextSubtree()) {
  71     nsIFrame* svgTextFrame = nsLayoutUtils::GetClosestFrameOfType(
  72         GetParent(), LayoutFrameType::SVGText);
  73     svgTextFrame->InvalidateFrame();
  74     return;
  75   }
  76   nsContainerFrame::InvalidateFrameWithRect(aRect, aDisplayItemKey,
  77                                             aRebuildDisplayItems);
  78 }
  79
  80 static inline bool IsMarginZero(const LengthPercentageOrAuto& aLength) {
  81   return aLength.IsAuto() ||
  82          nsLayoutUtils::IsMarginZero(aLength.AsLengthPercentage());
  83 }
  84
  85 /* virtual */
  86 bool nsInlineFrame::IsSelfEmpty() {
  87 #if 0
  88   // I used to think inline frames worked this way, but it seems they
  89   // don't.  At least not in our codebase.
  90   if (GetPresContext()->CompatibilityMode() == eCompatibility_FullStandards) {
  91     return false;
  92   }
  93 #endif
  94   const nsStyleMargin* margin = StyleMargin();
  95   const nsStyleBorder* border = StyleBorder();
  96   const nsStylePadding* padding = StylePadding();
  97   // Block-start and -end ignored, since they shouldn't affect things, but this
  98   // doesn't really match with nsLineLayout.cpp's setting of
  99   // ZeroEffectiveSpanBox, anymore, so what should this really be?
 100   WritingMode wm = GetWritingMode();
 101   bool haveStart, haveEnd;
 102
 103   auto HaveSide = [&](mozilla::Side aSide) -> bool {
 104     return border->GetComputedBorderWidth(aSide) != 0 ||
 105            !nsLayoutUtils::IsPaddingZero(padding->mPadding.Get(aSide)) ||
 106            !IsMarginZero(margin->mMargin.Get(aSide));
 107   };
 108   // Initially set up haveStart and haveEnd in terms of visual (LTR/TTB)
 109   // coordinates; we'll exchange them later if bidi-RTL is in effect to
 110   // get logical start and end flags.
 111   if (wm.IsVertical()) {
 112     haveStart = HaveSide(eSideTop);
 113     haveEnd = HaveSide(eSideBottom);
 114   } else {
 115     haveStart = HaveSide(eSideLeft);
 116     haveEnd = HaveSide(eSideRight);
 117   }
 118   if (haveStart || haveEnd) {
 119     // We skip this block and return false for box-decoration-break:clone since
 120     // in that case all the continuations will have the border/padding/margin.
 121     if (HasAnyStateBits(NS_FRAME_PART_OF_IBSPLIT) &&
 122         StyleBorder()->mBoxDecorationBreak == StyleBoxDecorationBreak::Slice) {
 123       // When direction=rtl, we need to consider logical rather than visual
 124       // start and end, so swap the flags.
 125       if (wm.IsBidiRTL()) {
 126         std::swap(haveStart, haveEnd);
 127       }
 128       // For ib-split frames, ignore things we know we'll skip in GetSkipSides.
 129       // XXXbz should we be doing this for non-ib-split frames too, in a more
 130       // general way?
 131
 132       // Get the first continuation eagerly, as a performance optimization, to
 133       // avoid having to get it twice..
 134       nsIFrame* firstCont = FirstContinuation();
 135       return (!haveStart || firstCont->FrameIsNonFirstInIBSplit()) &&
 136              (!haveEnd || firstCont->FrameIsNonLastInIBSplit());
 137     }
 138     return false;
 139   }
 140   return true;
 141 }
 142
 143 bool nsInlineFrame::IsEmpty() {
 144   if (!IsSelfEmpty()) {
 145     return false;
 146   }
 147
 148   for (nsIFrame* kid : mFrames) {
 149     if (!kid->IsEmpty()) return false;
 150   }
 151
 152   return true;
 153 }
 154
 155 nsIFrame::FrameSearchResult nsInlineFrame::PeekOffsetCharacter(
 156     bool aForward, int32_t* aOffset, PeekOffsetCharacterOptions aOptions) {
 157   // Override the implementation in nsFrame, to skip empty inline frames
 158   NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
 159   int32_t startOffset = *aOffset;
 160   if (startOffset < 0) startOffset = 1;
 161   if (aForward == (startOffset == 0)) {
 162     // We're before the frame and moving forward, or after it and moving
 163     // backwards: skip to the other side, but keep going.
 164     *aOffset = 1 - startOffset;
 165   }
 166   return CONTINUE;
 167 }
 168
 169 void nsInlineFrame::Destroy(DestroyContext& aContext) {
 170   nsFrameList* overflowFrames = GetOverflowFrames();
 171   if (overflowFrames) {
 172     // Fixup the parent pointers for any child frames on the OverflowList.
 173     // nsIFrame::DestroyFrom depends on that to find the sticky scroll
 174     // container (an ancestor).
 175     overflowFrames->ApplySetParent(this);
 176   }
 177   nsContainerFrame::Destroy(aContext);
 178 }
 179
 180 void nsInlineFrame::StealFrame(nsIFrame* aChild) {
 181   if (MaybeStealOverflowContainerFrame(aChild)) {
 182     return;
 183   }
 184
 185   nsInlineFrame* parent = this;
 186   do {
 187     if (parent->mFrames.StartRemoveFrame(aChild)) {
 188       return;
 189     }
 190
 191     // We didn't find the child in our principal child list.
 192     // Maybe it's on the overflow list?
 193     nsFrameList* frameList = parent->GetOverflowFrames();
 194     if (frameList && frameList->ContinueRemoveFrame(aChild)) {
 195       if (frameList->IsEmpty()) {
 196         parent->DestroyOverflowList();
 197       }
 198       return;
 199     }
 200
 201     // Due to our "lazy reparenting" optimization 'aChild' might not actually
 202     // be on any of our child lists, but instead in one of our next-in-flows.
 203     parent = static_cast<nsInlineFrame*>(parent->GetNextInFlow());
 204   } while (parent);
 205
 206   MOZ_ASSERT_UNREACHABLE("nsInlineFrame::StealFrame: can't find aChild");
 207 }
 208
 209 void nsInlineFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
 210                                      const nsDisplayListSet& aLists) {
 211   BuildDisplayListForInline(aBuilder, aLists);
 212
 213   // The sole purpose of this is to trigger display of the selection
 214   // window for Named Anchors, which don't have any children and
 215   // normally don't have any size, but in Editor we use CSS to display
 216   // an image to represent this "hidden" element.
 217   if (!mFrames.FirstChild()) {
 218     DisplaySelectionOverlay(aBuilder, aLists.Content());
 219   }
 220 }
 221
 222 //////////////////////////////////////////////////////////////////////
 223 // Reflow methods
 224
 225 /* virtual */
 226 void nsInlineFrame::AddInlineMinISize(gfxContext* aRenderingContext,
 227                                       nsIFrame::InlineMinISizeData* aData) {
 228   DoInlineMinISize(aRenderingContext, aData);
 229 }
 230
 231 /* virtual */
 232 void nsInlineFrame::AddInlinePrefISize(gfxContext* aRenderingContext,
 233                                        nsIFrame::InlinePrefISizeData* aData) {
 234   DoInlinePrefISize(aRenderingContext, aData);
 235 }
 236
 237 /* virtual */
 238 nsIFrame::SizeComputationResult nsInlineFrame::ComputeSize(
 239     gfxContext* aRenderingContext, WritingMode aWM, const LogicalSize& aCBSize,
 240     nscoord aAvailableISize, const LogicalSize& aMargin,
 241     const LogicalSize& aBorderPadding, const StyleSizeOverrides& aSizeOverrides,
 242     ComputeSizeFlags aFlags) {
 243   // Inlines and text don't compute size before reflow.
 244   return {LogicalSize(aWM, NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE),
 245           AspectRatioUsage::None};
 246 }
 247
 248 nsRect nsInlineFrame::ComputeTightBounds(DrawTarget* aDrawTarget) const {
 249   // be conservative
 250   if (Style()->HasTextDecorationLines()) {
 251     return InkOverflowRect();
 252   }
 253   return ComputeSimpleTightBounds(aDrawTarget);
 254 }
 255
 256 static void ReparentChildListStyle(nsPresContext* aPresContext,
 257                                    const nsFrameList::Slice& aFrames,
 258                                    nsIFrame* aParentFrame) {
 259   RestyleManager* restyleManager = aPresContext->RestyleManager();
 260
 261   for (nsIFrame* f : aFrames) {
 262     NS_ASSERTION(f->GetParent() == aParentFrame, "Bogus parentage");
 263     restyleManager->ReparentComputedStyleForFirstLine(f);
 264     nsLayoutUtils::MarkDescendantsDirty(f);
 265   }
 266 }
 267
 268 void nsInlineFrame::Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
 269                            const ReflowInput& aReflowInput,
 270                            nsReflowStatus& aStatus) {
 271   MarkInReflow();
 272   DO_GLOBAL_REFLOW_COUNT("nsInlineFrame");
 273   MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
 274
 275   if (!aReflowInput.mLineLayout) {
 276     NS_ERROR("must have non-null aReflowInput.mLineLayout");
 277     return;
 278   }
 279   if (IsFrameTreeTooDeep(aReflowInput, aMetrics, aStatus)) {
 280     return;
 281   }
 282
 283   bool lazilySetParentPointer = false;
 284
 285   // Check for an overflow list with our prev-in-flow
 286   nsInlineFrame* prevInFlow = (nsInlineFrame*)GetPrevInFlow();
 287   if (prevInFlow) {
 288     AutoFrameListPtr prevOverflowFrames(aPresContext,
 289                                         prevInFlow->StealOverflowFrames());
 290     if (prevOverflowFrames) {
 291       // When pushing and pulling frames we need to check for whether any
 292       // views need to be reparented.
 293       nsContainerFrame::ReparentFrameViewList(*prevOverflowFrames, prevInFlow,
 294                                               this);
 295
 296       // Check if we should do the lazilySetParentPointer optimization.
 297       // Only do it in simple cases where we're being reflowed for the
 298       // first time, nothing (e.g. bidi resolution) has already given
 299       // us children, and there's no next-in-flow, so all our frames
 300       // will be taken from prevOverflowFrames.
 301       if (HasAnyStateBits(NS_FRAME_FIRST_REFLOW) && mFrames.IsEmpty() &&
 302           !GetNextInFlow()) {
 303         // If our child list is empty, just put the new frames into it.
 304         // Note that we don't set the parent pointer for the new frames. Instead
 305         // wait to do this until we actually reflow the frame. If the overflow
 306         // list contains thousands of frames this is a big performance issue
 307         // (see bug #5588)
 308         mFrames = std::move(*prevOverflowFrames);
 309         lazilySetParentPointer = true;
 310       } else {
 311         // Insert the new frames at the beginning of the child list
 312         // and set their parent pointer
 313         const nsFrameList::Slice& newFrames =
 314             mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
 315         // If our prev in flow was under the first continuation of a first-line
 316         // frame then we need to reparent the ComputedStyles to remove the
 317         // the special first-line styling. In the lazilySetParentPointer case
 318         // we reparent the ComputedStyles when we set their parents in
 319         // nsInlineFrame::ReflowFrames and nsInlineFrame::ReflowInlineFrame.
 320         if (aReflowInput.mLineLayout->GetInFirstLine()) {
 321           ReparentChildListStyle(aPresContext, newFrames, this);
 322         }
 323       }
 324     }
 325   }
 326
 327   // It's also possible that we have an overflow list for ourselves
 328 #ifdef DEBUG
 329   if (HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
 330     // If it's our initial reflow, then we should not have an overflow list.
 331     // However, add an assertion in case we get reflowed more than once with
 332     // the initial reflow reason
 333     nsFrameList* overflowFrames = GetOverflowFrames();
 334     NS_ASSERTION(!overflowFrames || overflowFrames->IsEmpty(),
 335                  "overflow list is not empty for initial reflow");
 336   }
 337 #endif
 338   if (!HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
 339     DrainSelfOverflowListInternal(aReflowInput.mLineLayout->GetInFirstLine());
 340   }
 341
 342   // Set our own reflow input (additional state above and beyond aReflowInput).
 343   InlineReflowInput irs;
 344   irs.mPrevFrame = nullptr;
 345   irs.mLineContainer = aReflowInput.mLineLayout->LineContainerFrame();
 346   irs.mLineLayout = aReflowInput.mLineLayout;
 347   irs.mNextInFlow = (nsInlineFrame*)GetNextInFlow();
 348   irs.mSetParentPointer = lazilySetParentPointer;
 349
 350   if (mFrames.IsEmpty()) {
 351     // Try to pull over one frame before starting so that we know
 352     // whether we have an anonymous block or not.
 353     Unused << PullOneFrame(aPresContext, irs);
 354   }
 355
 356   ReflowFrames(aPresContext, aReflowInput, irs, aMetrics, aStatus);
 357
 358   ReflowAbsoluteFrames(aPresContext, aMetrics, aReflowInput, aStatus);
 359
 360   // Note: the line layout code will properly compute our
 361   // overflow-rect state for us.
 362 }
 363
 364 nsresult nsInlineFrame::AttributeChanged(int32_t aNameSpaceID,
 365                                          nsAtom* aAttribute, int32_t aModType) {
 366   nsresult rv =
 367       nsContainerFrame::AttributeChanged(aNameSpaceID, aAttribute, aModType);
 368
 369   if (NS_FAILED(rv)) {
 370     return rv;
 371   }
 372
 373   if (IsInSVGTextSubtree()) {
 374     SVGTextFrame* f = static_cast<SVGTextFrame*>(
 375         nsLayoutUtils::GetClosestFrameOfType(this, LayoutFrameType::SVGText));
 376     f->HandleAttributeChangeInDescendant(mContent->AsElement(), aNameSpaceID,
 377                                          aAttribute);
 378   }
 379
 380   return NS_OK;
 381 }
 382
 383 bool nsInlineFrame::DrainSelfOverflowListInternal(bool aInFirstLine) {
 384   AutoFrameListPtr overflowFrames(PresContext(), StealOverflowFrames());
 385   if (!overflowFrames || overflowFrames->IsEmpty()) {
 386     return false;
 387   }
 388
 389   // The frames on our own overflowlist may have been pushed by a
 390   // previous lazilySetParentPointer Reflow so we need to ensure the
 391   // correct parent pointer.  This is sometimes skipped by Reflow.
 392   nsIFrame* firstChild = overflowFrames->FirstChild();
 393   RestyleManager* restyleManager = PresContext()->RestyleManager();
 394   for (nsIFrame* f = firstChild; f; f = f->GetNextSibling()) {
 395     f->SetParent(this);
 396     if (MOZ_UNLIKELY(aInFirstLine)) {
 397       restyleManager->ReparentComputedStyleForFirstLine(f);
 398       nsLayoutUtils::MarkDescendantsDirty(f);
 399     }
 400   }
 401   mFrames.AppendFrames(nullptr, std::move(*overflowFrames));
 402   return true;
 403 }
 404
 405 /* virtual */
 406 bool nsInlineFrame::DrainSelfOverflowList() {
 407   nsIFrame* lineContainer = nsLayoutUtils::FindNearestBlockAncestor(this);
 408   // Add the eInFirstLine flag if we have a ::first-line ancestor frame.
 409   // No need to look further than the nearest line container though.
 410   bool inFirstLine = false;
 411   for (nsIFrame* p = GetParent(); p != lineContainer; p = p->GetParent()) {
 412     if (p->IsLineFrame()) {
 413       inFirstLine = true;
 414       break;
 415     }
 416   }
 417   return DrainSelfOverflowListInternal(inFirstLine);
 418 }
 419
 420 /* virtual */
 421 bool nsInlineFrame::CanContinueTextRun() const {
 422   // We can continue a text run through an inline frame
 423   return true;
 424 }
 425
 426 /* virtual */
 427 void nsInlineFrame::PullOverflowsFromPrevInFlow() {
 428   nsInlineFrame* prevInFlow = static_cast<nsInlineFrame*>(GetPrevInFlow());
 429   if (prevInFlow) {
 430     nsPresContext* presContext = PresContext();
 431     AutoFrameListPtr prevOverflowFrames(presContext,
 432                                         prevInFlow->StealOverflowFrames());
 433     if (prevOverflowFrames) {
 434       // Assume that our prev-in-flow has the same line container that we do.
 435       nsContainerFrame::ReparentFrameViewList(*prevOverflowFrames, prevInFlow,
 436                                               this);
 437       mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
 438     }
 439   }
 440 }
 441
 442 void nsInlineFrame::ReflowFrames(nsPresContext* aPresContext,
 443                                  const ReflowInput& aReflowInput,
 444                                  InlineReflowInput& irs, ReflowOutput& aMetrics,
 445                                  nsReflowStatus& aStatus) {
 446   MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
 447
 448   nsLineLayout* lineLayout = aReflowInput.mLineLayout;
 449   bool inFirstLine = aReflowInput.mLineLayout->GetInFirstLine();
 450   RestyleManager* restyleManager = aPresContext->RestyleManager();
 451   WritingMode frameWM = aReflowInput.GetWritingMode();
 452   WritingMode lineWM = aReflowInput.mLineLayout->mRootSpan->mWritingMode;
 453   LogicalMargin framePadding =
 454       aReflowInput.ComputedLogicalBorderPadding(frameWM);
 455   nscoord startEdge = 0;
 456   const bool boxDecorationBreakClone = MOZ_UNLIKELY(
 457       StyleBorder()->mBoxDecorationBreak == StyleBoxDecorationBreak::Clone);
 458   // Don't offset by our start borderpadding if we have a prev continuation or
 459   // if we're in a part of an {ib} split other than the first one. For
 460   // box-decoration-break:clone we always offset our start since all
 461   // continuations have border/padding.
 462   if ((!GetPrevContinuation() && !FrameIsNonFirstInIBSplit()) ||
 463       boxDecorationBreakClone) {
 464     startEdge = framePadding.IStart(frameWM);
 465   }
 466   nscoord availableISize = aReflowInput.AvailableISize();
 467   NS_ASSERTION(availableISize != NS_UNCONSTRAINEDSIZE,
 468                "should no longer use available widths");
 469   // Subtract off inline axis border+padding from availableISize
 470   availableISize -= startEdge;
 471   availableISize -= framePadding.IEnd(frameWM);
 472   lineLayout->BeginSpan(this, &aReflowInput, startEdge,
 473                         startEdge + availableISize, &mBaseline);
 474
 475   // First reflow our principal children.
 476   nsIFrame* frame = mFrames.FirstChild();
 477   bool done = false;
 478   while (frame) {
 479     // Check if we should lazily set the child frame's parent pointer.
 480     if (irs.mSetParentPointer) {
 481       nsIFrame* child = frame;
 482       do {
 483         child->SetParent(this);
 484         if (inFirstLine) {
 485           restyleManager->ReparentComputedStyleForFirstLine(child);
 486           nsLayoutUtils::MarkDescendantsDirty(child);
 487         }
 488         // We also need to do the same for |frame|'s next-in-flows that are in
 489         // the sibling list. Otherwise, if we reflow |frame| and it's complete
 490         // we'll crash when trying to delete its next-in-flow.
 491         // This scenario doesn't happen often, but it can happen.
 492         nsIFrame* nextSibling = child->GetNextSibling();
 493         child = child->GetNextInFlow();
 494         if (MOZ_UNLIKELY(child)) {
 495           while (child != nextSibling && nextSibling) {
 496             nextSibling = nextSibling->GetNextSibling();
 497           }
 498           if (!nextSibling) {
 499             child = nullptr;
 500           }
 501         }
 502         MOZ_ASSERT(!child || mFrames.ContainsFrame(child));
 503       } while (child);
 504
 505       // Fix the parent pointer for ::first-letter child frame next-in-flows,
 506       // so nsFirstLetterFrame::Reflow can destroy them safely (bug 401042).
 507       nsIFrame* realFrame = nsPlaceholderFrame::GetRealFrameFor(frame);
 508       if (realFrame->IsLetterFrame()) {
 509         nsIFrame* child = realFrame->PrincipalChildList().FirstChild();
 510         if (child) {
 511           NS_ASSERTION(child->IsTextFrame(), "unexpected frame type");
 512           nsIFrame* nextInFlow = child->GetNextInFlow();
 513           for (; nextInFlow; nextInFlow = nextInFlow->GetNextInFlow()) {
 514             NS_ASSERTION(nextInFlow->IsTextFrame(), "unexpected frame type");
 515             if (mFrames.ContainsFrame(nextInFlow)) {
 516               nextInFlow->SetParent(this);
 517               if (inFirstLine) {
 518                 restyleManager->ReparentComputedStyleForFirstLine(nextInFlow);
 519                 nsLayoutUtils::MarkDescendantsDirty(nextInFlow);
 520               }
 521             } else {
 522 #ifdef DEBUG
 523               // Once we find a next-in-flow that isn't ours none of the
 524               // remaining next-in-flows should be either.
 525               for (; nextInFlow; nextInFlow = nextInFlow->GetNextInFlow()) {
 526                 NS_ASSERTION(!mFrames.ContainsFrame(nextInFlow),
 527                              "unexpected letter frame flow");
 528               }
 529 #endif
 530               break;
 531             }
 532           }
 533         }
 534       }
 535     }
 536     MOZ_ASSERT(frame->GetParent() == this);
 537
 538     if (!done) {
 539       bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
 540       ReflowInlineFrame(aPresContext, aReflowInput, irs, frame, aStatus);
 541       done = aStatus.IsInlineBreak() ||
 542              (!reflowingFirstLetter && aStatus.IsIncomplete());
 543       if (done) {
 544         if (!irs.mSetParentPointer) {
 545           break;
 546         }
 547         // Keep reparenting the remaining siblings, but don't reflow them.
 548         nsFrameList* pushedFrames = GetOverflowFrames();
 549         if (pushedFrames && pushedFrames->FirstChild() == frame) {
 550           // Don't bother if |frame| was pushed to our overflow list.
 551           break;
 552         }
 553       } else {
 554         irs.mPrevFrame = frame;
 555       }
 556     }
 557     frame = frame->GetNextSibling();
 558   }
 559
 560   // Attempt to pull frames from our next-in-flow until we can't
 561   if (!done && GetNextInFlow()) {
 562     while (true) {
 563       bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
 564       if (!frame) {  // Could be non-null if we pulled a first-letter frame and
 565                      // it created a continuation, since we don't push those.
 566         frame = PullOneFrame(aPresContext, irs);
 567       }
 568 #ifdef NOISY_PUSHING
 569       printf("%p pulled up %p\n", this, frame);
 570 #endif
 571       if (!frame) {
 572         break;
 573       }
 574       ReflowInlineFrame(aPresContext, aReflowInput, irs, frame, aStatus);
 575       if (aStatus.IsInlineBreak() ||
 576           (!reflowingFirstLetter && aStatus.IsIncomplete())) {
 577         break;
 578       }
 579       irs.mPrevFrame = frame;
 580       frame = frame->GetNextSibling();
 581     }
 582   }
 583
 584   NS_ASSERTION(!aStatus.IsComplete() || !GetOverflowFrames(),
 585                "We can't be complete AND have overflow frames!");
 586
 587   // If after reflowing our children they take up no area then make
 588   // sure that we don't either.
 589   //
 590   // Note: CSS demands that empty inline elements still affect the
 591   // line-height calculations. However, continuations of an inline
 592   // that are empty we force to empty so that things like collapsed
 593   // whitespace in an inline element don't affect the line-height.
 594   aMetrics.ISize(lineWM) = lineLayout->EndSpan(this);
 595
 596   // Compute final width.
 597
 598   // XXX Note that that the padding start and end are in the frame's
 599   //     writing mode, but the metrics' inline-size is in the line's
 600   //     writing mode. This makes sense if the line and frame are both
 601   //     vertical or both horizontal, but what should happen with
 602   //     orthogonal inlines?
 603
 604   // Make sure to not include our start border and padding if we have a prev
 605   // continuation or if we're in a part of an {ib} split other than the first
 606   // one.  For box-decoration-break:clone we always include our start border
 607   // and padding since all continuations have them.
 608   if ((!GetPrevContinuation() && !FrameIsNonFirstInIBSplit()) ||
 609       boxDecorationBreakClone) {
 610     aMetrics.ISize(lineWM) += framePadding.IStart(frameWM);
 611   }
 612
 613   /*
 614    * We want to only apply the end border and padding if we're the last
 615    * continuation and either not in an {ib} split or the last part of it.  To
 616    * be the last continuation we have to be complete (so that we won't get a
 617    * next-in-flow) and have no non-fluid continuations on our continuation
 618    * chain.  For box-decoration-break:clone we always apply the end border and
 619    * padding since all continuations have them.
 620    */
 621   if ((aStatus.IsComplete() && !LastInFlow()->GetNextContinuation() &&
 622        !FrameIsNonLastInIBSplit()) ||
 623       boxDecorationBreakClone) {
 624     aMetrics.ISize(lineWM) += framePadding.IEnd(frameWM);
 625   }
 626
 627   nsLayoutUtils::SetBSizeFromFontMetrics(this, aMetrics, framePadding, lineWM,
 628                                          frameWM);
 629
 630   // For now our overflow area is zero. The real value will be
 631   // computed in |nsLineLayout::RelativePositionFrames|.
 632   aMetrics.mOverflowAreas.Clear();
 633
 634 #ifdef NOISY_FINAL_SIZE
 635   ListTag(stdout);
 636   printf(": metrics=%d,%d ascent=%d\n", aMetrics.Width(), aMetrics.Height(),
 637          aMetrics.BlockStartAscent());
 638 #endif
 639 }
 640
 641 // Returns whether there's any remaining frame to pull.
 642 /* static */
 643 bool nsInlineFrame::HasFramesToPull(nsInlineFrame* aNextInFlow) {
 644   while (aNextInFlow) {
 645     if (!aNextInFlow->mFrames.IsEmpty()) {
 646       return true;
 647     }
 648     if (const nsFrameList* overflow = aNextInFlow->GetOverflowFrames()) {
 649       if (!overflow->IsEmpty()) {
 650         return true;
 651       }
 652     }
 653     aNextInFlow = static_cast<nsInlineFrame*>(aNextInFlow->GetNextInFlow());
 654   }
 655   return false;
 656 }
 657
 658 void nsInlineFrame::ReflowInlineFrame(nsPresContext* aPresContext,
 659                                       const ReflowInput& aReflowInput,
 660                                       InlineReflowInput& irs, nsIFrame* aFrame,
 661                                       nsReflowStatus& aStatus) {
 662   nsLineLayout* lineLayout = aReflowInput.mLineLayout;
 663   bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
 664   bool pushedFrame;
 665   aStatus.Reset();
 666   lineLayout->ReflowFrame(aFrame, aStatus, nullptr, pushedFrame);
 667
 668   if (aStatus.IsInlineBreakBefore()) {
 669     if (aFrame != mFrames.FirstChild()) {
 670       // Change break-before status into break-after since we have
 671       // already placed at least one child frame. This preserves the
 672       // break-type so that it can be propagated upward.
 673       StyleClear oldClearType = aStatus.FloatClearType();
 674       aStatus.Reset();
 675       aStatus.SetIncomplete();
 676       aStatus.SetInlineLineBreakAfter(oldClearType);
 677       PushFrames(aPresContext, aFrame, irs.mPrevFrame, irs);
 678     } else {
 679       // Preserve reflow status when breaking-before our first child
 680       // and propagate it upward without modification.
 681     }
 682     return;
 683   }
 684
 685   // Create a next-in-flow if needed.
 686   if (!aStatus.IsFullyComplete()) {
 687     CreateNextInFlow(aFrame);
 688   }
 689
 690   if (aStatus.IsInlineBreakAfter()) {
 691     nsIFrame* nextFrame = aFrame->GetNextSibling();
 692     if (nextFrame) {
 693       aStatus.SetIncomplete();
 694       PushFrames(aPresContext, nextFrame, aFrame, irs);
 695     } else {
 696       // We must return an incomplete status if there are more child
 697       // frames remaining in a next-in-flow that follows this frame.
 698       if (HasFramesToPull(static_cast<nsInlineFrame*>(GetNextInFlow()))) {
 699         aStatus.SetIncomplete();
 700       }
 701     }
 702     return;
 703   }
 704
 705   if (!aStatus.IsFullyComplete() && !reflowingFirstLetter) {
 706     nsIFrame* nextFrame = aFrame->GetNextSibling();
 707     if (nextFrame) {
 708       PushFrames(aPresContext, nextFrame, aFrame, irs);
 709     }
 710   }
 711 }
 712
 713 nsIFrame* nsInlineFrame::PullOneFrame(nsPresContext* aPresContext,
 714                                       InlineReflowInput& irs) {
 715   nsIFrame* frame = nullptr;
 716   nsInlineFrame* nextInFlow = irs.mNextInFlow;
 717
 718 #ifdef DEBUG
 719   bool willPull = HasFramesToPull(nextInFlow);
 720 #endif
 721
 722   while (nextInFlow) {
 723     frame = nextInFlow->mFrames.FirstChild();
 724     if (!frame) {
 725       // The nextInFlow's principal list has no frames, try its overflow list.
 726       nsFrameList* overflowFrames = nextInFlow->GetOverflowFrames();
 727       if (overflowFrames) {
 728         frame = overflowFrames->RemoveFirstChild();
 729         if (overflowFrames->IsEmpty()) {
 730           // We're stealing the only frame - delete the overflow list.
 731           nextInFlow->DestroyOverflowList();
 732         } else {
 733           // We leave the remaining frames on the overflow list (rather than
 734           // putting them on nextInFlow's principal list) so we don't have to
 735           // set up the parent for them.
 736         }
 737         // ReparentFloatsForInlineChild needs it to be on a child list -
 738         // we remove it again below.
 739         nextInFlow->mFrames = nsFrameList(frame, frame);
 740       }
 741     }
 742
 743     if (frame) {
 744       // If our block has no next continuation, then any floats belonging to
 745       // the pulled frame must belong to our block already. This check ensures
 746       // we do no extra work in the common non-vertical-breaking case.
 747       if (irs.mLineContainer && irs.mLineContainer->GetNextContinuation()) {
 748         // The blockChildren.ContainsFrame check performed by
 749         // ReparentFloatsForInlineChild will be fast because frame's ancestor
 750         // will be the first child of its containing block.
 751         ReparentFloatsForInlineChild(irs.mLineContainer, frame, false);
 752       }
 753       nextInFlow->mFrames.RemoveFirstChild();
 754       // nsFirstLineFrame::PullOneFrame calls ReparentComputedStyle.
 755
 756       mFrames.InsertFrame(this, irs.mPrevFrame, frame);
 757       if (irs.mLineLayout) {
 758         irs.mLineLayout->SetDirtyNextLine();
 759       }
 760       nsContainerFrame::ReparentFrameView(frame, nextInFlow, this);
 761       break;
 762     }
 763     nextInFlow = static_cast<nsInlineFrame*>(nextInFlow->GetNextInFlow());
 764     irs.mNextInFlow = nextInFlow;
 765   }
 766
 767   MOZ_ASSERT(!!frame == willPull);
 768   return frame;
 769 }
 770
 771 void nsInlineFrame::PushFrames(nsPresContext* aPresContext,
 772                                nsIFrame* aFromChild, nsIFrame* aPrevSibling,
 773                                InlineReflowInput& aState) {
 774 #ifdef NOISY_PUSHING
 775   printf("%p pushing aFromChild %p, disconnecting from prev sib %p\n", this,
 776          aFromChild, aPrevSibling);
 777 #endif
 778
 779   PushChildrenToOverflow(aFromChild, aPrevSibling);
 780   if (aState.mLineLayout) {
 781     aState.mLineLayout->SetDirtyNextLine();
 782   }
 783 }
 784
 785 //////////////////////////////////////////////////////////////////////
 786
 787 LogicalSides nsInlineFrame::GetLogicalSkipSides() const {
 788   LogicalSides skip(mWritingMode);
 789   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
 790                    StyleBoxDecorationBreak::Clone)) {
 791     return skip;
 792   }
 793
 794   if (!IsFirst()) {
 795     nsInlineFrame* prev = (nsInlineFrame*)GetPrevContinuation();
 796     if (HasAnyStateBits(NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET) ||
 797         (prev && (prev->mRect.height || prev->mRect.width))) {
 798       // Prev continuation is not empty therefore we don't render our start
 799       // border edge.
 800       skip += LogicalSide::IStart;
 801     } else {
 802       // If the prev continuation is empty, then go ahead and let our start
 803       // edge border render.
 804     }
 805   }
 806   if (!IsLast()) {
 807     nsInlineFrame* next = (nsInlineFrame*)GetNextContinuation();
 808     if (HasAnyStateBits(NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET) ||
 809         (next && (next->mRect.height || next->mRect.width))) {
 810       // Next continuation is not empty therefore we don't render our end
 811       // border edge.
 812       skip += LogicalSide::IEnd;
 813     } else {
 814       // If the next continuation is empty, then go ahead and let our end
 815       // edge border render.
 816     }
 817   }
 818
 819   if (HasAnyStateBits(NS_FRAME_PART_OF_IBSPLIT)) {
 820     // All but the last part of an {ib} split should skip the "end" side (as
 821     // determined by this frame's direction) and all but the first part of such
 822     // a split should skip the "start" side.  But figuring out which part of
 823     // the split we are involves getting our first continuation, which might be
 824     // expensive.  So don't bother if we already have the relevant bits set.
 825     if (skip != LogicalSides(mWritingMode, LogicalSides::IBoth)) {
 826       // We're missing one of the skip bits, so check whether we need to set it.
 827       // Only get the first continuation once, as an optimization.
 828       nsIFrame* firstContinuation = FirstContinuation();
 829       if (firstContinuation->FrameIsNonLastInIBSplit()) {
 830         skip += LogicalSide::IEnd;
 831       }
 832       if (firstContinuation->FrameIsNonFirstInIBSplit()) {
 833         skip += LogicalSide::IStart;
 834       }
 835     }
 836   }
 837
 838   return skip;
 839 }
 840
 841 Maybe<nscoord> nsInlineFrame::GetNaturalBaselineBOffset(
 842     WritingMode aWM, BaselineSharingGroup aBaselineGroup,
 843     BaselineExportContext) const {
 844   if (aBaselineGroup == BaselineSharingGroup::Last) {
 845     return Nothing{};
 846   }
 847   return Some(mBaseline);
 848 }
 849
 850 #ifdef ACCESSIBILITY
 851 a11y::AccType nsInlineFrame::AccessibleType() {
 852   // FIXME(emilio): This is broken, if the image has its default `display` value
 853   // overridden. Should be somewhere else.
 854   if (mContent->IsHTMLElement(
 855           nsGkAtoms::img))  // Create accessible for broken <img>
 856     return a11y::eHyperTextType;
 857
 858   return a11y::eNoType;
 859 }
 860 #endif
 861
 862 void nsInlineFrame::UpdateStyleOfOwnedAnonBoxesForIBSplit(
 863     ServoRestyleState& aRestyleState) {
 864   MOZ_ASSERT(HasAnyStateBits(NS_FRAME_OWNS_ANON_BOXES),
 865              "Why did we get called?");
 866   MOZ_ASSERT(HasAnyStateBits(NS_FRAME_PART_OF_IBSPLIT),
 867              "Why did we have the NS_FRAME_OWNS_ANON_BOXES bit set?");
 868   // Note: this assert _looks_ expensive, but it's cheap in all the cases when
 869   // it passes!
 870   MOZ_ASSERT(nsLayoutUtils::FirstContinuationOrIBSplitSibling(this) == this,
 871              "Only the primary frame of the inline in a block-inside-inline "
 872              "split should have NS_FRAME_OWNS_ANON_BOXES");
 873   MOZ_ASSERT(mContent->GetPrimaryFrame() == this,
 874              "We should be the primary frame for our element");
 875
 876   nsIFrame* blockFrame = GetProperty(nsIFrame::IBSplitSibling());
 877   MOZ_ASSERT(blockFrame, "Why did we have an IB split?");
 878
 879   // The later inlines need to get our style.
 880   ComputedStyle* ourStyle = Style();
 881
 882   // The anonymous block's style inherits from ours, and we already have our new
 883   // ComputedStyle.
 884   RefPtr<ComputedStyle> newContext =
 885       aRestyleState.StyleSet().ResolveInheritingAnonymousBoxStyle(
 886           PseudoStyleType::mozBlockInsideInlineWrapper, ourStyle);
 887
 888   // We're guaranteed that newContext only differs from the old ComputedStyle on
 889   // the block in things they might inherit from us.  And changehint processing
 890   // guarantees walking the continuation and ib-sibling chains, so our existing
 891   // changehint being in aChangeList is good enough.  So we don't need to touch
 892   // aChangeList at all here.
 893
 894   while (blockFrame) {
 895     MOZ_ASSERT(!blockFrame->GetPrevContinuation(),
 896                "Must be first continuation");
 897
 898     MOZ_ASSERT(blockFrame->Style()->GetPseudoType() ==
 899                    PseudoStyleType::mozBlockInsideInlineWrapper,
 900                "Unexpected kind of ComputedStyle");
 901
 902     for (nsIFrame* cont = blockFrame; cont;
 903          cont = cont->GetNextContinuation()) {
 904       cont->SetComputedStyle(newContext);
 905     }
 906
 907     nsIFrame* nextInline = blockFrame->GetProperty(nsIFrame::IBSplitSibling());
 908
 909     // This check is here due to bug 1431232.  Please remove it once
 910     // that bug is fixed.
 911     if (MOZ_UNLIKELY(!nextInline)) {
 912       break;
 913     }
 914
 915     MOZ_ASSERT(nextInline, "There is always a trailing inline in an IB split");
 916
 917     for (nsIFrame* cont = nextInline; cont;
 918          cont = cont->GetNextContinuation()) {
 919       cont->SetComputedStyle(ourStyle);
 920     }
 921     blockFrame = nextInline->GetProperty(nsIFrame::IBSplitSibling());
 922   }
 923 }
 924
 925 //////////////////////////////////////////////////////////////////////
 926
 927 // nsLineFrame implementation
 928
 929 nsFirstLineFrame* NS_NewFirstLineFrame(PresShell* aPresShell,
 930                                        ComputedStyle* aStyle) {
 931   return new (aPresShell)
 932       nsFirstLineFrame(aStyle, aPresShell->GetPresContext());
 933 }
 934
 935 NS_IMPL_FRAMEARENA_HELPERS(nsFirstLineFrame)
 936
 937 void nsFirstLineFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
 938                             nsIFrame* aPrevInFlow) {
 939   nsInlineFrame::Init(aContent, aParent, aPrevInFlow);
 940   if (!aPrevInFlow) {
 941     MOZ_ASSERT(Style()->GetPseudoType() == PseudoStyleType::firstLine);
 942     return;
 943   }
 944
 945   // This frame is a continuation - fixup the computed style if aPrevInFlow
 946   // is the first-in-flow (the only one with a ::first-line pseudo).
 947   if (aPrevInFlow->Style()->GetPseudoType() == PseudoStyleType::firstLine) {
 948     MOZ_ASSERT(FirstInFlow() == aPrevInFlow);
 949     // Create a new ComputedStyle that is a child of the parent
 950     // ComputedStyle thus removing the ::first-line style. This way
 951     // we behave as if an anonymous (unstyled) span was the child
 952     // of the parent frame.
 953     ComputedStyle* parentContext = aParent->Style();
 954     RefPtr<ComputedStyle> newSC =
 955         PresContext()->StyleSet()->ResolveInheritingAnonymousBoxStyle(
 956             PseudoStyleType::mozLineFrame, parentContext);
 957     SetComputedStyle(newSC);
 958   } else {
 959     MOZ_ASSERT(FirstInFlow() != aPrevInFlow);
 960     MOZ_ASSERT(aPrevInFlow->Style()->GetPseudoType() ==
 961                PseudoStyleType::mozLineFrame);
 962   }
 963 }
 964
 965 #ifdef DEBUG_FRAME_DUMP
 966 nsresult nsFirstLineFrame::GetFrameName(nsAString& aResult) const {
 967   return MakeFrameName(u"Line"_ns, aResult);
 968 }
 969 #endif
 970
 971 nsIFrame* nsFirstLineFrame::PullOneFrame(nsPresContext* aPresContext,
 972                                          InlineReflowInput& irs) {
 973   nsIFrame* frame = nsInlineFrame::PullOneFrame(aPresContext, irs);
 974   if (frame && !GetPrevInFlow()) {
 975     // We are a first-line frame. Fixup the child frames
 976     // style-context that we just pulled.
 977     NS_ASSERTION(frame->GetParent() == this, "Incorrect parent?");
 978     aPresContext->RestyleManager()->ReparentComputedStyleForFirstLine(frame);
 979     nsLayoutUtils::MarkDescendantsDirty(frame);
 980   }
 981   return frame;
 982 }
 983
 984 void nsFirstLineFrame::Reflow(nsPresContext* aPresContext,
 985                               ReflowOutput& aMetrics,
 986                               const ReflowInput& aReflowInput,
 987                               nsReflowStatus& aStatus) {
 988   MarkInReflow();
 989   MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
 990
 991   if (nullptr == aReflowInput.mLineLayout) {
 992     return;  // XXX does this happen? why?
 993   }
 994
 995   // Check for an overflow list with our prev-in-flow
 996   nsFirstLineFrame* prevInFlow = (nsFirstLineFrame*)GetPrevInFlow();
 997   if (prevInFlow) {
 998     AutoFrameListPtr prevOverflowFrames(aPresContext,
 999                                         prevInFlow->StealOverflowFrames());
1000     if (prevOverflowFrames) {
1001       // Reparent the new frames and their ComputedStyles.
1002       const nsFrameList::Slice& newFrames =
1003           mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
1004       ReparentChildListStyle(aPresContext, newFrames, this);
1005     }
1006   }
1007
1008   // It's also possible that we have an overflow list for ourselves.
1009   DrainSelfOverflowList();
1010
1011   // Set our own reflow input (additional state above and beyond aReflowInput).
1012   InlineReflowInput irs;
1013   irs.mPrevFrame = nullptr;
1014   irs.mLineContainer = aReflowInput.mLineLayout->LineContainerFrame();
1015   irs.mLineLayout = aReflowInput.mLineLayout;
1016   irs.mNextInFlow = (nsInlineFrame*)GetNextInFlow();
1017
1018   bool wasEmpty = mFrames.IsEmpty();
1019   if (wasEmpty) {
1020     // Try to pull over one frame before starting so that we know
1021     // whether we have an anonymous block or not.
1022     PullOneFrame(aPresContext, irs);
1023   }
1024
1025   if (nullptr == GetPrevInFlow()) {
1026     // XXX This is pretty sick, but what we do here is to pull-up, in
1027     // advance, all of the next-in-flows children. We re-resolve their
1028     // style while we are at at it so that when we reflow they have
1029     // the right style.
1030     //
1031     // All of this is so that text-runs reflow properly.
1032     irs.mPrevFrame = mFrames.LastChild();
1033     for (;;) {
1034       nsIFrame* frame = PullOneFrame(aPresContext, irs);
1035       if (!frame) {
1036         break;
1037       }
1038       irs.mPrevFrame = frame;
1039     }
1040     irs.mPrevFrame = nullptr;
1041   }
1042
1043   NS_ASSERTION(!aReflowInput.mLineLayout->GetInFirstLine(),
1044                "Nested first-line frames? BOGUS");
1045   aReflowInput.mLineLayout->SetInFirstLine(true);
1046   ReflowFrames(aPresContext, aReflowInput, irs, aMetrics, aStatus);
1047   aReflowInput.mLineLayout->SetInFirstLine(false);
1048
1049   ReflowAbsoluteFrames(aPresContext, aMetrics, aReflowInput, aStatus);
1050
1051   // Note: the line layout code will properly compute our overflow state for us
1052 }
1053
1054 /* virtual */
1055 void nsFirstLineFrame::PullOverflowsFromPrevInFlow() {
1056   nsFirstLineFrame* prevInFlow =
1057       static_cast<nsFirstLineFrame*>(GetPrevInFlow());
1058   if (prevInFlow) {
1059     nsPresContext* presContext = PresContext();
1060     AutoFrameListPtr prevOverflowFrames(presContext,
1061                                         prevInFlow->StealOverflowFrames());
1062     if (prevOverflowFrames) {
1063       // Assume that our prev-in-flow has the same line container that we do.
1064       const nsFrameList::Slice& newFrames =
1065           mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
1066       ReparentChildListStyle(presContext, newFrames, this);
1067     }
1068   }
1069 }
1070
1071 /* virtual */
1072 bool nsFirstLineFrame::DrainSelfOverflowList() {
1073   AutoFrameListPtr overflowFrames(PresContext(), StealOverflowFrames());
1074   if (overflowFrames) {
1075     bool result = !overflowFrames->IsEmpty();
1076     const nsFrameList::Slice& newFrames =
1077         mFrames.AppendFrames(nullptr, std::move(*overflowFrames));
1078     ReparentChildListStyle(PresContext(), newFrames, this);
1079     return result;
1080   }
1081   return false;
1082 }