Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1048 insertions, 0 deletions

diff --git a/layout/generic/nsBlockFrame.h b/layout/generic/nsBlockFrame.h
new file mode 100644
index 0000000000..8d7bcdb8d0
--- /dev/null
+++ b/layout/generic/nsBlockFrame.h
@@ -0,0 +1,1048 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * rendering object for CSS display:block, inline-block, and list-item
+ * boxes, also used for various anonymous boxes
+ */
+
+#ifndef nsBlockFrame_h___
+#define nsBlockFrame_h___
+
+#include "nsContainerFrame.h"
+#include "nsHTMLParts.h"
+#include "nsLineBox.h"
+#include "nsCSSPseudoElements.h"
+#include "nsFloatManager.h"
+
+enum class LineReflowStatus {
+  // The line was completely reflowed and fit in available width, and we should
+  // try to pull up content from the next line if possible.
+  OK,
+  // The line was completely reflowed and fit in available width, but we should
+  // not try to pull up content from the next line.
+  Stop,
+  // We need to reflow the line again at its current vertical position. The
+  // new reflow should not try to pull up any frames from the next line.
+  RedoNoPull,
+  // We need to reflow the line again using the floats from its height
+  // this reflow, since its height made it hit floats that were not
+  // adjacent to its top.
+  RedoMoreFloats,
+  // We need to reflow the line again at a lower vertical postion where there
+  // may be more horizontal space due to different float configuration.
+  RedoNextBand,
+  // The line did not fit in the available vertical space. Try pushing it to
+  // the next page or column if it's not the first line on the current
+  // page/column.
+  Truncated
+};
+
+class nsBlockInFlowLineIterator;
+namespace mozilla {
+class BlockReflowState;
+class PresShell;
+class ServoRestyleState;
+class ServoStyleSet;
+}  // namespace mozilla
+
+/**
+ * Some invariants:
+ * -- The overflow out-of-flows list contains the out-of-
+ * flow frames whose placeholders are in the overflow list.
+ * -- A given piece of content has at most one placeholder
+ * frame in a block's normal child list.
+ * -- While a block is being reflowed, and from then until
+ * its next-in-flow is reflowed it may have a
+ * PushedFloatProperty frame property that points to
+ * an nsFrameList. This list contains continuations for
+ * floats whose prev-in-flow is in the block's regular float
+ * list and first-in-flows of floats that did not fit, but
+ * whose placeholders are in the block or one of its
+ * prev-in-flows.
+ * -- In all these frame lists, if there are two frames for
+ * the same content appearing in the list, then the frames
+ * appear with the prev-in-flow before the next-in-flow.
+ * -- While reflowing a block, its overflow line list
+ * will usually be empty but in some cases will have lines
+ * (while we reflow the block at its shrink-wrap width).
+ * In this case any new overflowing content must be
+ * prepended to the overflow lines.
+ */
+
+/*
+ * Base class for block and inline frames.
+ * The block frame has an additional child list, FrameChildListID::Absolute,
+ * which contains the absolutely positioned frames.
+ */
+class nsBlockFrame : public nsContainerFrame {
+  using BlockReflowState = mozilla::BlockReflowState;
+
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(nsBlockFrame)
+
+  typedef nsLineList::iterator LineIterator;
+  typedef nsLineList::const_iterator ConstLineIterator;
+  typedef nsLineList::reverse_iterator ReverseLineIterator;
+  typedef nsLineList::const_reverse_iterator ConstReverseLineIterator;
+
+  LineIterator LinesBegin() { return mLines.begin(); }
+  LineIterator LinesEnd() { return mLines.end(); }
+  ConstLineIterator LinesBegin() const { return mLines.begin(); }
+  ConstLineIterator LinesEnd() const { return mLines.end(); }
+  ReverseLineIterator LinesRBegin() { return mLines.rbegin(); }
+  ReverseLineIterator LinesREnd() { return mLines.rend(); }
+  ConstReverseLineIterator LinesRBegin() const { return mLines.rbegin(); }
+  ConstReverseLineIterator LinesREnd() const { return mLines.rend(); }
+  LineIterator LinesBeginFrom(nsLineBox* aList) { return mLines.begin(aList); }
+  ReverseLineIterator LinesRBeginFrom(nsLineBox* aList) {
+    return mLines.rbegin(aList);
+  }
+
+  // Methods declared to be used in 'range-based-for-loop'
+  nsLineList& Lines() { return mLines; }
+  const nsLineList& Lines() const { return mLines; }
+
+  friend nsBlockFrame* NS_NewBlockFrame(mozilla::PresShell* aPresShell,
+                                        ComputedStyle* aStyle);
+
+  // nsQueryFrame
+  NS_DECL_QUERYFRAME
+
+  // nsIFrame
+  void Init(nsIContent* aContent, nsContainerFrame* aParent,
+            nsIFrame* aPrevInFlow) override;
+  void SetInitialChildList(ChildListID aListID,
+                           nsFrameList&& aChildList) override;
+  void AppendFrames(ChildListID aListID, nsFrameList&& aFrameList) override;
+  void InsertFrames(ChildListID aListID, nsIFrame* aPrevFrame,
+                    const nsLineList::iterator* aPrevFrameLine,
+                    nsFrameList&& aFrameList) override;
+  void RemoveFrame(DestroyContext&, ChildListID, nsIFrame* aOldFrame) override;
+  nsContainerFrame* GetContentInsertionFrame() override;
+  void AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult) override;
+  const nsFrameList& GetChildList(ChildListID aListID) const override;
+  void GetChildLists(nsTArray<ChildList>* aLists) const override;
+  nscoord SynthesizeFallbackBaseline(
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;
+  BaselineSharingGroup GetDefaultBaselineSharingGroup() const override {
+    return BaselineSharingGroup::Last;
+  }
+  Maybe<nscoord> GetNaturalBaselineBOffset(
+      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
+      BaselineExportContext aExportContext) const override;
+  nscoord GetCaretBaseline() const override;
+  void Destroy(DestroyContext&) override;
+
+  bool IsFloatContainingBlock() const override;
+  void BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                        const nsDisplayListSet& aLists) override;
+  bool IsFrameOfType(uint32_t aFlags) const override {
+    return nsContainerFrame::IsFrameOfType(
+        aFlags & ~(nsIFrame::eCanContainOverflowContainers));
+  }
+
+  void InvalidateFrame(uint32_t aDisplayItemKey = 0,
+                       bool aRebuildDisplayItems = true) override;
+  void InvalidateFrameWithRect(const nsRect& aRect,
+                               uint32_t aDisplayItemKey = 0,
+                               bool aRebuildDisplayItems = true) override;
+
+#ifdef DEBUG_FRAME_DUMP
+  void List(FILE* out = stderr, const char* aPrefix = "",
+            ListFlags aFlags = ListFlags()) const override;
+  nsresult GetFrameName(nsAString& aResult) const override;
+#endif
+
+#ifdef DEBUG
+  const char* LineReflowStatusToString(
+      LineReflowStatus aLineReflowStatus) const;
+#endif
+
+#ifdef ACCESSIBILITY
+  mozilla::a11y::AccType AccessibleType() override;
+#endif
+
+  // Line cursor methods to speed up line searching in which one query result
+  // is expected to be close to the next in general. This is mainly for
+  // searching line(s) containing a point. It is also used as a cache for local
+  // computation. The basic idea for the former is that we set the cursor
+  // property if the lines' overflowArea.InkOverflow().ys and
+  // overflowArea.InkOverflow().yMosts are non-decreasing
+  // (considering only non-empty overflowArea.InkOverflow()s; empty
+  // overflowArea.InkOverflow()s never participate in event handling
+  // or painting), and the block has sufficient number of lines. The
+  // cursor property points to a "recently used" line. If we get a
+  // series of requests that work on lines
+  // "near" the cursor, then we can find those nearby lines quickly by
+  // starting our search at the cursor.
+
+  // We have two independent line cursors, one used for display-list building
+  // and the other for a11y or other frame queries. Either or both may be
+  // present at any given time. When we reflow or otherwise munge the lines,
+  // both cursors will be cleared.
+  // The display cursor is only created and used if the lines satisfy the non-
+  // decreasing y-coordinate condition (see SetupLineCursorForDisplay comment
+  // below), whereas the query cursor may be created for any block. The two
+  // are separated so creating a cursor for a11y queries (eg GetRenderedText)
+  // does not risk confusing the display-list building code.
+
+  // Clear out line cursors because we're disturbing the lines (i.e., Reflow)
+  void ClearLineCursors() {
+    if (MaybeHasLineCursor()) {
+      ClearLineCursorForDisplay();
+      ClearLineCursorForQuery();
+      RemoveStateBits(NS_BLOCK_HAS_LINE_CURSOR);
+    }
+    RemoveProperty(LineIteratorProperty());
+  }
+  void ClearLineCursorForDisplay() {
+    RemoveProperty(LineCursorPropertyDisplay());
+  }
+  void ClearLineCursorForQuery() { RemoveProperty(LineCursorPropertyQuery()); }
+
+  // Get the first line that might contain y-coord 'y', or nullptr if you must
+  // search all lines. If nonnull is returned then we guarantee that the lines'
+  // combinedArea.ys and combinedArea.yMosts are non-decreasing.
+  // The actual line returned might not contain 'y', but if not, it is
+  // guaranteed to be before any line which does contain 'y'.
+  nsLineBox* GetFirstLineContaining(nscoord y);
+
+  // Ensure the frame has a display-list line cursor, initializing it to the
+  // first line if it is not already present. (If there's an existing cursor,
+  // it is left untouched.) Only call this if you guarantee that the lines'
+  // combinedArea.ys and combinedArea.yMosts are non-decreasing.
+  void SetupLineCursorForDisplay();
+
+  // Ensure the frame has a query line cursor, initializing it to the first
+  // line if it is not already present. (If there's an existing cursor, it is
+  // left untouched.)
+  void SetupLineCursorForQuery();
+
+  void ChildIsDirty(nsIFrame* aChild) override;
+
+  bool IsEmpty() override;
+  bool CachedIsEmpty() override;
+  bool IsSelfEmpty() override;
+
+  // Given that we have a ::marker frame, does it actually draw something, i.e.,
+  // do we have either a 'list-style-type' or 'list-style-image' that is
+  // not 'none', and no 'content'?
+  bool MarkerIsEmpty() const;
+
+  /**
+   * Return true if this frame has a ::marker frame.
+   */
+  bool HasMarker() const { return HasOutsideMarker() || HasInsideMarker(); }
+
+  /**
+   * @return true if this frame has an inside ::marker frame.
+   */
+  bool HasInsideMarker() const {
+    return HasAnyStateBits(NS_BLOCK_FRAME_HAS_INSIDE_MARKER);
+  }
+
+  /**
+   * @return true if this frame has an outside ::marker frame.
+   */
+  bool HasOutsideMarker() const {
+    return HasAnyStateBits(NS_BLOCK_FRAME_HAS_OUTSIDE_MARKER);
+  }
+
+  /**
+   * @return the ::marker frame or nullptr if we don't have one.
+   */
+  nsIFrame* GetMarker() const {
+    nsIFrame* outside = GetOutsideMarker();
+    return outside ? outside : GetInsideMarker();
+  }
+
+  /**
+   * @return the first-letter frame or nullptr if we don't have one.
+   */
+  nsIFrame* GetFirstLetter() const;
+
+  /**
+   * @return the ::first-line frame or nullptr if we don't have one.
+   */
+  nsIFrame* GetFirstLineFrame() const;
+
+  void MarkIntrinsicISizesDirty() override;
+
+ private:
+  void CheckIntrinsicCacheAgainstShrinkWrapState();
+
+  template <typename LineIteratorType>
+  Maybe<nscoord> GetBaselineBOffset(LineIteratorType aStart,
+                                    LineIteratorType aEnd,
+                                    mozilla::WritingMode aWM,
+                                    BaselineSharingGroup aBaselineGroup,
+                                    BaselineExportContext aExportContext) const;
+
+ public:
+  nscoord GetMinISize(gfxContext* aRenderingContext) override;
+  nscoord GetPrefISize(gfxContext* aRenderingContext) override;
+
+  nsRect ComputeTightBounds(DrawTarget* aDrawTarget) const override;
+
+  nsresult GetPrefWidthTightBounds(gfxContext* aContext, nscoord* aX,
+                                   nscoord* aXMost) override;
+
+  /**
+   * Compute the final block size of this frame.
+   *
+   * @param aState BlockReflowState passed from parent during reflow.
+   *        Note: aState.mReflowStatus is mostly an "input" parameter. When this
+   *        method is called, it should represent what our status would be as if
+   *        we were shrinkwrapping our children's block-size. This method will
+   *        then adjust it before returning if our status is different in light
+   *        of our actual final block-size and current page/column's available
+   *        block-size.
+   * @param aBEndEdgeOfChildren The distance between this frame's block-start
+   *        border-edge and the block-end edge of our last child's border-box.
+   *        This is effectively our block-start border-padding plus the
+   *        block-size of our children, precomputed outside of this function.
+   * @return our final block-size with respect to aReflowInput's writing-mode.
+   */
+  nscoord ComputeFinalBSize(BlockReflowState& aState,
+                            nscoord aBEndEdgeOfChildren);
+
+  void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
+              const ReflowInput& aReflowInput,
+              nsReflowStatus& aStatus) override;
+
+  /**
+   * Move any frames on our overflow list to the end of our principal list.
+   * @return true if there were any overflow frames
+   */
+  bool DrainSelfOverflowList() override;
+
+  void StealFrame(nsIFrame* aChild) override;
+
+  void DeleteNextInFlowChild(DestroyContext&, nsIFrame* aNextInFlow,
+                             bool aDeletingEmptyFrames) override;
+
+  /**
+   * This is a special method that allows a child class of nsBlockFrame to
+   * return a special, customized nsStyleText object to the nsLineLayout
+   * constructor. It is used when the nsBlockFrame child needs to specify its
+   * custom rendering style.
+   */
+  virtual const nsStyleText* StyleTextForLineLayout();
+
+  /**
+   * Determines whether the collapsed margin carried out of the last
+   * line includes the margin-top of a line with clearance (in which
+   * case we must avoid collapsing that margin with our bottom margin)
+   */
+  bool CheckForCollapsedBEndMarginFromClearanceLine();
+
+  static nsresult GetCurrentLine(BlockReflowState* aState,
+                                 nsLineBox** aOutCurrentLine);
+
+  /**
+   * Determine if this block is a margin root at the top/bottom edges.
+   */
+  void IsMarginRoot(bool* aBStartMarginRoot, bool* aBEndMarginRoot);
+
+  static bool BlockNeedsFloatManager(nsIFrame* aBlock);
+
+  /**
+   * Returns whether aFrame is a block frame that will wrap its contents
+   * around floats intruding on it from the outside.  (aFrame need not
+   * be a block frame, but if it's not, the result will be false.)
+   *
+   * Note: We often use the term "float-avoiding block" to refer to
+   * block-level frames for whom this function returns false.
+   */
+  static bool BlockCanIntersectFloats(nsIFrame* aFrame);
+
+  /**
+   * Returns the inline size that needs to be cleared past floats for
+   * blocks that avoid (i.e. cannot intersect) floats.  aState must already
+   * have GetFloatAvailableSpace called on it for the block-dir position that
+   * we care about (which need not be its current mBCoord)
+   */
+  struct FloatAvoidingISizeToClear {
+    // Note that we care about the inline-start margin but can ignore
+    // the inline-end margin.
+    nscoord marginIStart, borderBoxISize;
+  };
+  static FloatAvoidingISizeToClear ISizeToClearPastFloats(
+      const BlockReflowState& aState,
+      const mozilla::LogicalRect& aFloatAvailableSpace,
+      nsIFrame* aFloatAvoidingBlock);
+
+  /**
+   * Creates a contination for aFloat and adds it to the list of overflow
+   * floats. Also updates aState.mReflowStatus to include the float's
+   * incompleteness. Must only be called while this block frame is in reflow.
+   * aFloatStatus must be the float's true, unmodified reflow status.
+   */
+  void SplitFloat(BlockReflowState& aState, nsIFrame* aFloat,
+                  const nsReflowStatus& aFloatStatus);
+
+  /**
+   * Walks up the frame tree, starting with aCandidate, and returns the first
+   * block frame that it encounters.
+   */
+  static nsBlockFrame* GetNearestAncestorBlock(nsIFrame* aCandidate);
+
+  struct FrameLines {
+    nsLineList mLines;
+    nsFrameList mFrames;
+  };
+
+  /**
+   * Update the styles of our various pseudo-elements (marker, first-line,
+   * etc, but _not_ first-letter).
+   */
+  void UpdatePseudoElementStyles(mozilla::ServoRestyleState& aRestyleState);
+
+  // Update our first-letter styles during stylo post-traversal.  This needs to
+  // be done at a slightly different time than our other pseudo-elements.
+  void UpdateFirstLetterStyle(mozilla::ServoRestyleState& aRestyleState);
+
+ protected:
+  explicit nsBlockFrame(ComputedStyle* aStyle, nsPresContext* aPresContext,
+                        ClassID aID = kClassID)
+      : nsContainerFrame(aStyle, aPresContext, aID) {
+#ifdef DEBUG
+    InitDebugFlags();
+#endif
+  }
+
+  virtual ~nsBlockFrame();
+
+#ifdef DEBUG
+  already_AddRefed<ComputedStyle> GetFirstLetterStyle(
+      nsPresContext* aPresContext);
+#endif
+
+  NS_DECLARE_FRAME_PROPERTY_WITHOUT_DTOR(LineCursorPropertyDisplay, nsLineBox)
+  NS_DECLARE_FRAME_PROPERTY_WITHOUT_DTOR(LineCursorPropertyQuery, nsLineBox)
+  // Note that the NS_BLOCK_HAS_LINE_CURSOR flag does not necessarily mean the
+  // cursor is present, as it covers both the "display" and "query" cursors,
+  // but may remain set if they have been separately deleted. In such a case,
+  // the Get* accessors will be slightly more expensive, but will still safely
+  // return null if the cursor is absent.
+  bool MaybeHasLineCursor() {
+    return HasAnyStateBits(NS_BLOCK_HAS_LINE_CURSOR);
+  }
+  nsLineBox* GetLineCursorForDisplay() {
+    return MaybeHasLineCursor() ? GetProperty(LineCursorPropertyDisplay())
+                                : nullptr;
+  }
+  nsLineBox* GetLineCursorForQuery() {
+    return MaybeHasLineCursor() ? GetProperty(LineCursorPropertyQuery())
+                                : nullptr;
+  }
+
+  nsLineBox* NewLineBox(nsIFrame* aFrame, bool aIsBlock) {
+    return NS_NewLineBox(PresShell(), aFrame, aIsBlock);
+  }
+  nsLineBox* NewLineBox(nsLineBox* aFromLine, nsIFrame* aFrame,
+                        int32_t aCount) {
+    return NS_NewLineBox(PresShell(), aFromLine, aFrame, aCount);
+  }
+  void FreeLineBox(nsLineBox* aLine) {
+    if (aLine == GetLineCursorForDisplay()) {
+      ClearLineCursorForDisplay();
+    }
+    if (aLine == GetLineCursorForQuery()) {
+      ClearLineCursorForQuery();
+    }
+    aLine->Destroy(PresShell());
+  }
+  /**
+   * Helper method for StealFrame.
+   */
+  void RemoveFrameFromLine(nsIFrame* aChild, nsLineList::iterator aLine,
+                           nsFrameList& aFrameList, nsLineList& aLineList);
+
+  void TryAllLines(nsLineList::iterator* aIterator,
+                   nsLineList::iterator* aStartIterator,
+                   nsLineList::iterator* aEndIterator, bool* aInOverflowLines,
+                   FrameLines** aOverflowLines);
+
+  /** move the frames contained by aLine by aDeltaBCoord
+   * if aLine is a block, its child floats are added to the state manager
+   */
+  void SlideLine(BlockReflowState& aState, nsLineBox* aLine,
+                 nscoord aDeltaBCoord);
+
+  void UpdateLineContainerSize(nsLineBox* aLine,
+                               const nsSize& aNewContainerSize);
+
+  // helper for SlideLine and UpdateLineContainerSize
+  void MoveChildFramesOfLine(nsLineBox* aLine, nscoord aDeltaBCoord);
+
+  void ComputeFinalSize(const ReflowInput& aReflowInput,
+                        BlockReflowState& aState, ReflowOutput& aMetrics,
+                        nscoord* aBEndEdgeOfChildren);
+
+  /**
+   * Helper method for Reflow(). Computes the overflow areas created by our
+   * children, and includes them into aOverflowAreas.
+   */
+  void ComputeOverflowAreas(mozilla::OverflowAreas& aOverflowAreas,
+                            nscoord aBEndEdgeOfChildren,
+                            const nsStyleDisplay* aDisplay) const;
+
+  /**
+   * Helper method for ComputeOverflowAreas(). Incorporates aBEndEdgeOfChildren
+   * into the aOverflowAreas.
+   */
+  void ConsiderBlockEndEdgeOfChildren(mozilla::OverflowAreas& aOverflowAreas,
+                                      nscoord aBEndEdgeOfChildren,
+                                      const nsStyleDisplay* aDisplay) const;
+
+  /**
+   * Add the frames in aFrameList to this block after aPrevSibling.
+   * This block thinks in terms of lines, but the frame construction code
+   * knows nothing about lines at all so we need to find the line that
+   * contains aPrevSibling and add aFrameList after aPrevSibling on that line.
+   * New lines are created as necessary to handle block data in aFrameList.
+   * This function will clear aFrameList.
+   *
+   * aPrevSiblingLine, if present, must be the line containing aPrevSibling.
+   * Providing it will make this function faster.
+   */
+  void AddFrames(nsFrameList&& aFrameList, nsIFrame* aPrevSibling,
+                 const nsLineList::iterator* aPrevSiblingLine);
+
+  // Return the :-moz-block-ruby-content child frame, if any.
+  // (It's non-null only if this block frame is for 'display:block ruby'.)
+  nsContainerFrame* GetRubyContentPseudoFrame();
+
+  /**
+   * Perform Bidi resolution on this frame
+   */
+  nsresult ResolveBidi();
+
+  /**
+   * Test whether the frame is a form control in a visual Bidi page.
+   * This is necessary for backwards-compatibility, because most visual
+   * pages use logical order for form controls so that they will
+   * display correctly on native widgets in OSs with Bidi support
+   * @param aPresContext the pres context
+   * @return whether the frame is a BIDI form control
+   */
+  bool IsVisualFormControl(nsPresContext* aPresContext);
+
+ public:
+  /**
+   * Helper function for the frame ctor to register a ::marker frame.
+   */
+  void SetMarkerFrameForListItem(nsIFrame* aMarkerFrame);
+
+  /**
+   * Does all the real work for removing aDeletedFrame
+   * -- finds the line containing aDeletedFrame
+   * -- removes all aDeletedFrame next-in-flows (or all continuations,
+   * if REMOVE_FIXED_CONTINUATIONS is given)
+   * -- marks lines dirty as needed
+   * -- marks textruns dirty (unless FRAMES_ARE_EMPTY is given, in which
+   * case textruns do not need to be dirtied)
+   * -- destroys all removed frames
+   */
+  enum { REMOVE_FIXED_CONTINUATIONS = 0x02, FRAMES_ARE_EMPTY = 0x04 };
+  void DoRemoveFrame(DestroyContext&, nsIFrame* aDeletedFrame, uint32_t aFlags);
+
+  void ReparentFloats(nsIFrame* aFirstFrame, nsBlockFrame* aOldParent,
+                      bool aReparentSiblings);
+
+  bool ComputeCustomOverflow(mozilla::OverflowAreas&) override;
+
+  void UnionChildOverflow(mozilla::OverflowAreas&) override;
+
+  /**
+   * Load all of aFrame's floats into the float manager iff aFrame is not a
+   * block formatting context. Handles all necessary float manager translations;
+   * assumes float manager is in aFrame's parent's coord system.
+   *
+   * Safe to call on non-blocks (does nothing).
+   */
+  static void RecoverFloatsFor(nsIFrame* aFrame, nsFloatManager& aFloatManager,
+                               mozilla::WritingMode aWM,
+                               const nsSize& aContainerSize);
+
+  /**
+   * Determine if we have any pushed floats from a previous continuation.
+   *
+   * @returns true, if any of the floats at the beginning of our mFloats list
+   *          have the NS_FRAME_IS_PUSHED_FLOAT bit set; false otherwise.
+   */
+  bool HasPushedFloatsFromPrevContinuation() const;
+
+  // @see nsIFrame::AddSizeOfExcludingThisForTree
+  void AddSizeOfExcludingThisForTree(nsWindowSizes&) const override;
+
+  /**
+   * Clears any -webkit-line-clamp ellipsis on a line in this block or one
+   * of its descendants.
+   */
+  void ClearLineClampEllipsis();
+
+  /**
+   * Returns whether this block is in a -webkit-line-clamp context. That is,
+   * whether this block is in a block formatting-context whose root block has
+   * -webkit-line-clamp: <n>.
+   */
+  bool IsInLineClampContext() const;
+
+ protected:
+  /** grab overflow lines from this block's prevInFlow, and make them
+   * part of this block's mLines list.
+   * @return true if any lines were drained.
+   */
+  bool DrainOverflowLines();
+
+  /**
+   * @return false iff this block does not have a float on any child list.
+   * This function is O(1).
+   */
+  bool MaybeHasFloats() const {
+    if (!mFloats.IsEmpty()) {
+      return true;
+    }
+    // XXX this could be replaced with HasPushedFloats() if we enforced
+    // removing the property when the frame list becomes empty.
+    nsFrameList* list = GetPushedFloats();
+    if (list && !list->IsEmpty()) {
+      return true;
+    }
+    // For the OverflowOutOfFlowsProperty I think we do enforce that, but it's
+    // a mix of out-of-flow frames, so that's why the method name has "Maybe".
+    return HasAnyStateBits(NS_BLOCK_HAS_OVERFLOW_OUT_OF_FLOWS);
+  }
+
+  /**
+   * Moves frames from our PushedFloats list back into our mFloats list.
+   */
+  void DrainSelfPushedFloats();
+
+  /**
+   * First calls DrainSelfPushedFloats() then grabs pushed floats from this
+   * block's prev-in-flow, and splice them into this block's mFloats list too.
+   */
+  void DrainPushedFloats();
+
+  /** Load all our floats into the float manager (without reflowing them).
+   *  Assumes float manager is in our own coordinate system.
+   */
+  void RecoverFloats(nsFloatManager& aFloatManager, mozilla::WritingMode aWM,
+                     const nsSize& aContainerSize);
+
+  /** Reflow pushed floats
+   */
+  void ReflowPushedFloats(BlockReflowState& aState,
+                          mozilla::OverflowAreas& aOverflowAreas);
+
+  /**
+   * Find any trailing BR clear from the last line of this block (or from its
+   * prev-in-flows).
+   */
+  mozilla::StyleClear FindTrailingClear();
+
+  /**
+   * Remove a float from our float list.
+   */
+  void RemoveFloat(nsIFrame* aFloat);
+  /**
+   * Remove a float from the float cache for the line its placeholder is on.
+   */
+  void RemoveFloatFromFloatCache(nsIFrame* aFloat);
+
+  void CollectFloats(nsIFrame* aFrame, nsFrameList& aList,
+                     bool aCollectFromSiblings) {
+    if (MaybeHasFloats()) {
+      DoCollectFloats(aFrame, aList, aCollectFromSiblings);
+    }
+  }
+  void DoCollectFloats(nsIFrame* aFrame, nsFrameList& aList,
+                       bool aCollectFromSiblings);
+
+  // Remove a float, abs, rel positioned frame from the appropriate block's list
+  static void DoRemoveOutOfFlowFrame(DestroyContext&, nsIFrame*);
+
+  /** set up the conditions necessary for an resize reflow
+   * the primary task is to mark the minimumly sufficient lines dirty.
+   */
+  void PrepareResizeReflow(BlockReflowState& aState);
+
+  /** reflow all lines that have been marked dirty */
+  void ReflowDirtyLines(BlockReflowState& aState);
+
+  /** Mark a given line dirty due to reflow being interrupted on or before it */
+  void MarkLineDirtyForInterrupt(nsLineBox* aLine);
+
+  //----------------------------------------
+  // Methods for line reflow
+  /**
+   * Reflow a line.
+   *
+   * @param aState
+   *   the current reflow input
+   * @param aLine
+   *   the line to reflow.  can contain a single block frame or contain 1 or
+   *   more inline frames.
+   * @param aKeepReflowGoing [OUT]
+   *   indicates whether the caller should continue to reflow more lines
+   */
+  void ReflowLine(BlockReflowState& aState, LineIterator aLine,
+                  bool* aKeepReflowGoing);
+
+  // Return false if it needs another reflow because of reduced space
+  // between floats that are next to it (but not next to its top), and
+  // return true otherwise.
+  bool PlaceLine(BlockReflowState& aState, nsLineLayout& aLineLayout,
+                 LineIterator aLine,
+                 nsFloatManager::SavedState* aFloatStateBeforeLine,
+                 nsFlowAreaRect& aFlowArea,      // in-out
+                 nscoord& aAvailableSpaceBSize,  // in-out
+                 bool* aKeepReflowGoing);
+
+  /**
+   * If NS_BLOCK_LOOK_FOR_DIRTY_FRAMES is set, call MarkLineDirty
+   * on any line with a child frame that is dirty.
+   */
+  void LazyMarkLinesDirty();
+
+  /**
+   * Mark |aLine| dirty, and, if necessary because of possible
+   * pull-up, mark the previous line dirty as well. Also invalidates textruns
+   * on those lines because the text in the lines might have changed due to
+   * addition/removal of frames.
+   * @param aLine the line to mark dirty
+   * @param aLineList the line list containing that line
+   */
+  void MarkLineDirty(LineIterator aLine, const nsLineList* aLineList);
+
+  // XXX where to go
+  bool IsLastLine(BlockReflowState& aState, LineIterator aLine);
+
+  void DeleteLine(BlockReflowState& aState, nsLineList::iterator aLine,
+                  nsLineList::iterator aLineEnd);
+
+  //----------------------------------------
+  // Methods for individual frame reflow
+
+  bool ShouldApplyBStartMargin(BlockReflowState& aState, nsLineBox* aLine);
+
+  void ReflowBlockFrame(BlockReflowState& aState, LineIterator aLine,
+                        bool* aKeepGoing);
+
+  void ReflowInlineFrames(BlockReflowState& aState, LineIterator aLine,
+                          bool* aKeepLineGoing);
+
+  void DoReflowInlineFrames(
+      BlockReflowState& aState, nsLineLayout& aLineLayout, LineIterator aLine,
+      nsFlowAreaRect& aFloatAvailableSpace, nscoord& aAvailableSpaceBSize,
+      nsFloatManager::SavedState* aFloatStateBeforeLine, bool* aKeepReflowGoing,
+      LineReflowStatus* aLineReflowStatus, bool aAllowPullUp);
+
+  void ReflowInlineFrame(BlockReflowState& aState, nsLineLayout& aLineLayout,
+                         LineIterator aLine, nsIFrame* aFrame,
+                         LineReflowStatus* aLineReflowStatus);
+
+  // @param aReflowStatus an incomplete status indicates the float should be
+  //        split but only if the available block-size is constrained.
+  void ReflowFloat(BlockReflowState& aState, ReflowInput& aFloatRI,
+                   nsIFrame* aFloat, nsReflowStatus& aReflowStatus);
+
+  //----------------------------------------
+  // Methods for pushing/pulling lines/frames
+
+  /**
+   * Create a next-in-flow, if necessary, for aFrame. If a new frame is
+   * created, place it in aLine if aLine is not null.
+   * @param aState the block reflow state
+   * @param aLine where to put a new frame
+   * @param aFrame the frame
+   * @return true if a new frame was created, false if not
+   */
+  bool CreateContinuationFor(BlockReflowState& aState, nsLineBox* aLine,
+                             nsIFrame* aFrame);
+
+  /**
+   * Set line-break-before status in aState.mReflowStatus because aLine cannot
+   * be placed on this page/column and we don't want to break within ourselves.
+   * Also, mark the aLine dirty, and set aKeepReflowGoing to false;
+   */
+  void SetBreakBeforeStatusBeforeLine(BlockReflowState& aState,
+                                      LineIterator aLine,
+                                      bool* aKeepReflowGoing);
+
+  /**
+   * Push aLine (and any after it), since it cannot be placed on this
+   * page/column.  Set aKeepReflowGoing to false and set
+   * flag aState.mReflowStatus as incomplete.
+   */
+  void PushTruncatedLine(BlockReflowState& aState, LineIterator aLine,
+                         bool* aKeepReflowGoing);
+
+  void SplitLine(BlockReflowState& aState, nsLineLayout& aLineLayout,
+                 LineIterator aLine, nsIFrame* aFrame,
+                 LineReflowStatus* aLineReflowStatus);
+
+  /**
+   * Pull a frame from the next available location (one of our lines or
+   * one of our next-in-flows lines).
+   * @return the pulled frame or nullptr
+   */
+  nsIFrame* PullFrame(BlockReflowState& aState, LineIterator aLine);
+
+  /**
+   * Try to pull a frame out of a line pointed at by aFromLine.
+   *
+   * Note: pulling a frame from a line that is a place-holder frame
+   * doesn't automatically remove the corresponding float from the
+   * line's float array. This happens indirectly: either the line gets
+   * emptied (and destroyed) or the line gets reflowed (because we mark
+   * it dirty) and the code at the top of ReflowLine empties the
+   * array. So eventually, it will be removed, just not right away.
+   *
+   * @return the pulled frame or nullptr
+   */
+  nsIFrame* PullFrameFrom(nsLineBox* aLine, nsBlockFrame* aFromContainer,
+                          nsLineList::iterator aFromLine);
+
+  /**
+   * Push the line after aLineBefore to the overflow line list.
+   * @param aLineBefore a line in 'mLines' (or LinesBegin() when
+   *        pushing the first line)
+   */
+  void PushLines(BlockReflowState& aState, nsLineList::iterator aLineBefore);
+
+  void PropagateFloatDamage(BlockReflowState& aState, nsLineBox* aLine,
+                            nscoord aDeltaBCoord);
+
+  void CheckFloats(BlockReflowState& aState);
+
+  //----------------------------------------
+  // List handling kludge
+
+  void ReflowOutsideMarker(nsIFrame* aMarkerFrame, BlockReflowState& aState,
+                           ReflowOutput& aMetrics, nscoord aLineTop);
+
+  //----------------------------------------
+
+  NS_DECLARE_FRAME_PROPERTY_DELETABLE(LineIteratorProperty, nsLineIterator);
+
+  bool CanProvideLineIterator() const final { return true; }
+  nsILineIterator* GetLineIterator() final;
+
+ public:
+  bool HasOverflowLines() const {
+    return HasAnyStateBits(NS_BLOCK_HAS_OVERFLOW_LINES);
+  }
+  FrameLines* GetOverflowLines() const;
+
+ protected:
+  FrameLines* RemoveOverflowLines();
+  void SetOverflowLines(FrameLines* aOverflowLines);
+  void DestroyOverflowLines();
+
+  /**
+   * This class is useful for efficiently modifying the out of flow
+   * overflow list. It gives the client direct writable access to
+   * the frame list temporarily but ensures that property is only
+   * written back if absolutely necessary.
+   */
+  struct nsAutoOOFFrameList {
+    nsFrameList mList;
+
+    explicit nsAutoOOFFrameList(nsBlockFrame* aBlock)
+        : mPropValue(aBlock->GetOverflowOutOfFlows()), mBlock(aBlock) {
+      if (mPropValue) {
+        mList = std::move(*mPropValue);
+      }
+    }
+    ~nsAutoOOFFrameList() {
+      mBlock->SetOverflowOutOfFlows(std::move(mList), mPropValue);
+    }
+
+   protected:
+    nsFrameList* const mPropValue;
+    nsBlockFrame* const mBlock;
+  };
+  friend struct nsAutoOOFFrameList;
+
+  nsFrameList* GetOverflowOutOfFlows() const;
+
+  // This takes ownership of the frames in aList.
+  void SetOverflowOutOfFlows(nsFrameList&& aList, nsFrameList* aPropValue);
+
+  /**
+   * @return the inside ::marker frame or nullptr if we don't have one.
+   */
+  nsIFrame* GetInsideMarker() const;
+
+  /**
+   * @return the outside ::marker frame or nullptr if we don't have one.
+   */
+  nsIFrame* GetOutsideMarker() const;
+
+  /**
+   * @return the outside ::marker frame list frame property.
+   */
+  nsFrameList* GetOutsideMarkerList() const;
+
+  /**
+   * @return true if this frame has pushed floats.
+   */
+  bool HasPushedFloats() const {
+    return HasAnyStateBits(NS_BLOCK_HAS_PUSHED_FLOATS);
+  }
+
+  // Get the pushed floats list, which is used for *temporary* storage
+  // of floats during reflow, between when we decide they don't fit in
+  // this block until our next continuation takes them.
+  nsFrameList* GetPushedFloats() const;
+  // Get the pushed floats list, or if there is not currently one,
+  // make a new empty one.
+  nsFrameList* EnsurePushedFloats();
+  // Remove and return the pushed floats list.
+  nsFrameList* RemovePushedFloats();
+
+#ifdef DEBUG
+  void VerifyLines(bool aFinalCheckOK);
+  void VerifyOverflowSituation();
+  int32_t GetDepth() const;
+#endif
+
+  nscoord mCachedMinISize = NS_INTRINSIC_ISIZE_UNKNOWN;
+  nscoord mCachedPrefISize = NS_INTRINSIC_ISIZE_UNKNOWN;
+
+  nsLineList mLines;
+
+  // List of all floats in this block
+  // XXXmats blocks rarely have floats, make it a frame property
+  nsFrameList mFloats;
+
+  friend class mozilla::BlockReflowState;
+  friend class nsBlockInFlowLineIterator;
+
+#ifdef DEBUG
+ public:
+  static bool gLamePaintMetrics;
+  static bool gLameReflowMetrics;
+  static bool gNoisy;
+  static bool gNoisyDamageRepair;
+  static bool gNoisyIntrinsic;
+  static bool gNoisyReflow;
+  static bool gReallyNoisyReflow;
+  static bool gNoisyFloatManager;
+  static bool gVerifyLines;
+  static bool gDisableResizeOpt;
+
+  static int32_t gNoiseIndent;
+
+  static const char* kReflowCommandType[];
+
+ protected:
+  static void InitDebugFlags();
+#endif
+};
+
+#ifdef DEBUG
+class AutoNoisyIndenter {
+ public:
+  explicit AutoNoisyIndenter(bool aDoIndent) : mIndented(aDoIndent) {
+    if (mIndented) {
+      nsBlockFrame::gNoiseIndent++;
+    }
+  }
+  ~AutoNoisyIndenter() {
+    if (mIndented) {
+      nsBlockFrame::gNoiseIndent--;
+    }
+  }
+
+ private:
+  bool mIndented;
+};
+#endif
+
+/**
+ * Iterates over all lines in the prev-in-flows/next-in-flows of this block.
+ */
+class nsBlockInFlowLineIterator {
+ public:
+  typedef nsBlockFrame::LineIterator LineIterator;
+  /**
+   * Set up the iterator to point to aLine which must be a normal line
+   * in aFrame (not an overflow line).
+   */
+  nsBlockInFlowLineIterator(nsBlockFrame* aFrame, LineIterator aLine);
+  /**
+   * Set up the iterator to point to the first line found starting from
+   * aFrame. Sets aFoundValidLine to false if there is no such line.
+   * After aFoundValidLine has returned false, don't call any methods on this
+   * object again.
+   */
+  nsBlockInFlowLineIterator(nsBlockFrame* aFrame, bool* aFoundValidLine);
+  /**
+   * Set up the iterator to point to the line that contains aFindFrame (either
+   * directly or indirectly).  If aFrame is out of flow, or contained in an
+   * out-of-flow, finds the line containing the out-of-flow's placeholder. If
+   * the frame is not found, sets aFoundValidLine to false. After
+   * aFoundValidLine has returned false, don't call any methods on this
+   * object again.
+   */
+  nsBlockInFlowLineIterator(nsBlockFrame* aFrame, nsIFrame* aFindFrame,
+                            bool* aFoundValidLine);
+
+  // Allow to be uninitialized (and then assigned from another object).
+  nsBlockInFlowLineIterator() : mFrame(nullptr) {}
+
+  LineIterator GetLine() { return mLine; }
+  bool IsLastLineInList();
+  nsBlockFrame* GetContainer() { return mFrame; }
+  bool GetInOverflow() { return mLineList != &mFrame->mLines; }
+
+  /**
+   * Returns the current line list we're iterating, null means
+   * we're iterating |mLines| of the container.
+   */
+  nsLineList* GetLineList() { return mLineList; }
+
+  /**
+   * Returns the end-iterator of whatever line list we're in.
+   */
+  LineIterator End();
+
+  /**
+   * Returns false if there are no more lines. After this has returned false,
+   * don't call any methods on this object again.
+   */
+  bool Next();
+  /**
+   * Returns false if there are no more lines. After this has returned false,
+   * don't call any methods on this object again.
+   */
+  bool Prev();
+
+  // XXX nsBlockFrame uses this internally in one place.  Try to remove it.
+  // XXX uhm, and nsBidiPresUtils::Resolve too.
+  nsBlockInFlowLineIterator(nsBlockFrame* aFrame, LineIterator aLine,
+                            bool aInOverflow);
+
+ private:
+  nsBlockFrame* mFrame;
+  LineIterator mLine;
+  nsLineList* mLineList;  // the line list mLine is in
+
+  /**
+   * Moves iterator to next valid line reachable from the current block.
+   * Returns false if there are no valid lines.
+   */
+  bool FindValidLine();
+};
+
+#endif /* nsBlockFrame_h___ */