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/* -*- 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 */
/* rendering object for CSS "display: flex" and "display: -webkit-box" */
#ifndef nsFlexContainerFrame_h___
#define nsFlexContainerFrame_h___
#include <tuple>
#include "mozilla/dom/FlexBinding.h"
#include "mozilla/UniquePtr.h"
#include "nsContainerFrame.h"
namespace mozilla {
class LogicalPoint;
class PresShell;
} // namespace mozilla
nsContainerFrame* NS_NewFlexContainerFrame(mozilla::PresShell* aPresShell,
mozilla::ComputedStyle* aStyle);
* These structures are used to capture data during reflow to be
* extracted by devtools via Chrome APIs. The structures are only
* created when requested in GetFlexFrameWithComputedInfo(), and
* the structures are attached to the nsFlexContainerFrame via the
* FlexContainerInfo property.
struct ComputedFlexItemInfo {
nsCOMPtr<nsINode> mNode;
nsRect mFrameRect;
* mMainBaseSize is a measure of the size of the item in the main
* axis before the flex sizing algorithm is applied. In the spec,
* this is called "flex base size", but we use this name to connect
* the value to the other main axis sizes.
nscoord mMainBaseSize;
* mMainDeltaSize is the amount that the flex sizing algorithm
* adds to the mMainBaseSize, before clamping to mMainMinSize and
* mMainMaxSize. This can be thought of as the amount by which the
* flex layout algorithm "wants" to shrink or grow the item, and
* would do, if it was unconstrained. Since the flex sizing
* algorithm proceeds linearly, the mMainDeltaSize for an item only
* respects the resolved size of items already frozen.
nscoord mMainDeltaSize;
nscoord mMainMinSize;
nscoord mMainMaxSize;
nscoord mCrossMinSize;
nscoord mCrossMaxSize;
mozilla::dom::FlexItemClampState mClampState;
struct ComputedFlexLineInfo {
nsTArray<ComputedFlexItemInfo> mItems;
nscoord mCrossStart;
nscoord mCrossSize;
nscoord mFirstBaselineOffset;
nscoord mLastBaselineOffset;
mozilla::dom::FlexLineGrowthState mGrowthState;
struct ComputedFlexContainerInfo {
nsTArray<ComputedFlexLineInfo> mLines;
mozilla::dom::FlexPhysicalDirection mMainAxisDirection;
mozilla::dom::FlexPhysicalDirection mCrossAxisDirection;
* Helper class to get the orientation of a flex container's axes.
class MOZ_STACK_CLASS FlexboxAxisInfo final {
explicit FlexboxAxisInfo(const nsIFrame* aFlexContainer);
// Is our main axis the inline axis? (Are we 'flex-direction:row[-reverse]'?)
bool mIsRowOriented = true;
// Is our main axis in the opposite direction as mWM's corresponding axis?
// (e.g. RTL vs LTR)
bool mIsMainAxisReversed = false;
// Is our cross axis in the opposite direction as mWM's corresponding axis?
// (e.g. BTT vs TTB)
bool mIsCrossAxisReversed = false;
// Helpers for constructor which determine the orientation of our axes, based
// on legacy box properties (-webkit-box-orient, -webkit-box-direction) or
// modern flexbox properties (flex-direction, flex-wrap) depending on whether
// the flex container is a "legacy box" (as determined by IsLegacyBox).
void InitAxesFromLegacyProps(const nsIFrame* aFlexContainer);
void InitAxesFromModernProps(const nsIFrame* aFlexContainer);
* This is the rendering object used for laying out elements with
* "display: flex" or "display: inline-flex".
* We also use this class for elements with "display: -webkit-box" or
* "display: -webkit-inline-box" (but not "-moz-box" / "-moz-inline-box" --
* those are rendered with old-school XUL frame classes).
* Note: we represent the -webkit-box family of properties (-webkit-box-orient,
* -webkit-box-flex, etc.) as aliases for their -moz equivalents. And for
* -webkit-{inline-}box containers, nsFlexContainerFrame will honor those
* "legacy" properties for alignment/flexibility/etc. *instead of* honoring the
* modern flexbox & alignment properties. For brevity, many comments in
* nsFlexContainerFrame.cpp simply refer to these properties using their
* "-webkit" versions, since we're mostly expecting to encounter them in that
* form. (Technically, the "-moz" versions of these properties *can* influence
* layout here as well (since that's what the -webkit versions are aliased to)
* -- but only inside of a "display:-webkit-{inline-}box" container.)
class nsFlexContainerFrame final : public nsContainerFrame {
// Factory method:
friend nsContainerFrame* NS_NewFlexContainerFrame(
mozilla::PresShell* aPresShell, ComputedStyle* aStyle);
// Forward-decls of helper classes
class FlexItem;
class FlexLine;
class FlexboxAxisTracker;
struct StrutInfo;
class CachedBAxisMeasurement;
class CachedFlexItemData;
struct SharedFlexData;
class FlexItemIterator;
// nsIFrame overrides
void Init(nsIContent* aContent, nsContainerFrame* aParent,
nsIFrame* aPrevInFlow) override;
bool IsFrameOfType(uint32_t aFlags) const override {
return nsContainerFrame::IsFrameOfType(
aFlags & ~(nsIFrame::eCanContainOverflowContainers));
void BuildDisplayList(nsDisplayListBuilder* aBuilder,
const nsDisplayListSet& aLists) override;
void MarkIntrinsicISizesDirty() override;
void Reflow(nsPresContext* aPresContext, ReflowOutput& aReflowOutput,
const ReflowInput& aReflowInput,
nsReflowStatus& aStatus) override;
nscoord GetMinISize(gfxContext* aRenderingContext) override;
nscoord GetPrefISize(gfxContext* aRenderingContext) override;
nsresult GetFrameName(nsAString& aResult) const override;
nscoord GetLogicalBaseline(mozilla::WritingMode aWM) const override;
bool GetVerticalAlignBaseline(mozilla::WritingMode aWM,
nscoord* aBaseline) const override {
return GetNaturalBaselineBOffset(aWM, BaselineSharingGroup::First,
bool GetNaturalBaselineBOffset(mozilla::WritingMode aWM,
BaselineSharingGroup aBaselineGroup,
nscoord* aBaseline) const override {
if (StyleDisplay()->IsContainLayout() ||
return false;
*aBaseline = aBaselineGroup == BaselineSharingGroup::First
? mBaselineFromLastReflow
: mLastBaselineFromLastReflow;
return true;
* Returns the effective value of -webkit-line-clamp for this flex container.
* This will be 0 if the property is 'none', or if the element is not
* display:-webkit-(inline-)box and -webkit-box-orient:vertical.
uint32_t GetLineClampValue() const;
// nsContainerFrame overrides
bool DrainSelfOverflowList() override;
void AppendFrames(ChildListID aListID, nsFrameList& aFrameList) override;
void InsertFrames(ChildListID aListID, nsIFrame* aPrevFrame,
const nsLineList::iterator* aPrevFrameLine,
nsFrameList& aFrameList) override;
void RemoveFrame(ChildListID aListID, nsIFrame* aOldFrame) override;
mozilla::StyleAlignFlags CSSAlignmentForAbsPosChild(
const ReflowInput& aChildRI,
mozilla::LogicalAxis aLogicalAxis) const override;
* Helper function to calculate packing space and initial offset of alignment
* subjects in MainAxisPositionTracker() and CrossAxisPositionTracker() for
* space-between, space-around, and space-evenly.
* * @param aNumThingsToPack Number of alignment subjects.
* @param aAlignVal Value for align-content or
* justify-content.
* @param aFirstSubjectOffset Outparam for first subject offset.
* @param aNumPackingSpacesRemaining Outparam for number of equal-sized
* packing spaces to apply between each
* alignment subject.
* @param aPackingSpaceRemaining Outparam for total amount of packing
* space to be divided up.
static void CalculatePackingSpace(
uint32_t aNumThingsToPack,
const mozilla::StyleContentDistribution& aAlignVal,
nscoord* aFirstSubjectOffset, uint32_t* aNumPackingSpacesRemaining,
nscoord* aPackingSpaceRemaining);
* This property is created by a call to
* nsFlexContainerFrame::GetFlexFrameWithComputedInfo.
* This function should only be called on a nsFlexContainerFrame
* that has just been returned by a call to
* GetFlexFrameWithComputedInfo.
const ComputedFlexContainerInfo* GetFlexContainerInfo() {
const ComputedFlexContainerInfo* info = GetProperty(FlexContainerInfo());
"Property generation wasn't requested. "
"This is a known issue in Print Preview. "
"See Bug 1157012.");
return info;
* Return aFrame as a flex frame after ensuring it has computed flex info.
* @return nullptr if aFrame is null or doesn't have a flex frame
* as its content insertion frame.
* @note this might destroy layout/style data since it may flush layout.
static nsFlexContainerFrame* GetFlexFrameWithComputedInfo(nsIFrame* aFrame);
* Given a frame for a flex item, this method returns true IFF that flex
* item's inline axis is the same as (i.e. not orthogonal to) its flex
* container's main axis.
* (This method is only intended to be used from external
* callers. Inside of flex reflow code, FlexItem::IsInlineAxisMainAxis() is
* equivalent & more optimal.)
* @param aFrame a flex item (must return true from IsFlexItem)
* @return true iff aFrame's inline axis is the same as (i.e. not orthogonal
* to) its flex container's main axis. Otherwise, false.
static bool IsItemInlineAxisMainAxis(nsIFrame* aFrame);
* Returns true iff the given computed 'flex-basis' & main-size property
* values collectively represent a used flex-basis of 'content'.
* @param aFlexBasis the computed 'flex-basis' for a flex item.
* @param aMainSize the computed main-size property for a flex item.
static bool IsUsedFlexBasisContent(const mozilla::StyleFlexBasis& aFlexBasis,
const mozilla::StyleSize& aMainSize);
* Callback for nsIFrame::MarkIntrinsicISizesDirty() on a flex item.
static void MarkCachedFlexMeasurementsDirty(nsIFrame* aItemFrame);
// Protected constructor & destructor
explicit nsFlexContainerFrame(ComputedStyle* aStyle,
nsPresContext* aPresContext)
: nsContainerFrame(aStyle, aPresContext, kClassID) {}
virtual ~nsFlexContainerFrame();
// Protected flex-container-specific methods / member-vars
* This method does the bulk of the flex layout, implementing the algorithm
* (with a few initialization pieces happening in the caller, Reflow().
* (The logic behind the division of work between Reflow and DoFlexLayout is
* as follows: DoFlexLayout() begins at the step that we have to jump back
* to, if we find any visibility:collapse children, and Reflow() does
* everything before that point.)
* @param aTentativeContentBoxMainSize the "tentative" content-box main-size
* of the flex container; "tentative"
* because it may be unconstrained or may
* run off the page.
* @param aTentativeContentBoxCrossSize the "tentative" content-box cross-size
* of the flex container; "tentative"
* because it may be unconstrained or may
* run off the page.
struct FlexLayoutResult final {
// The flex lines of the flex container.
nsTArray<FlexLine> mLines;
// The absolutely-positioned flex children.
nsTArray<nsIFrame*> mPlaceholders;
// The final content-box main-size of the flex container as if there's no
// fragmentation.
nscoord mContentBoxMainSize = NS_UNCONSTRAINEDSIZE;
// The final content-box cross-size of the flex container as if there's no
// fragmentation.
nscoord mContentBoxCrossSize = NS_UNCONSTRAINEDSIZE;
// The flex container's ascent, derived from any baseline-aligned flex items
// in the first flex line, if any such items exist. Otherwise, nscoord_MIN.
FlexLayoutResult DoFlexLayout(
const ReflowInput& aReflowInput,
const nscoord aTentativeContentBoxMainSize,
const nscoord aTentativeContentBoxCrossSize,
const FlexboxAxisTracker& aAxisTracker, nscoord aMainGapSize,
nscoord aCrossGapSize, bool aHasLineClampEllipsis,
nsTArray<StrutInfo>& aStruts,
ComputedFlexContainerInfo* const aContainerInfo);
* If our devtools have requested a ComputedFlexContainerInfo for this flex
* container, this method ensures that we have one (and if one already exists,
* this method reinitializes it to look like a freshly-created one).
* @return the pointer to a freshly created or reinitialized
* ComputedFlexContainerInfo if our devtools have requested it;
* otherwise nullptr.
ComputedFlexContainerInfo* CreateOrClearFlexContainerInfo();
* Helpers for DoFlexLayout to computed fields in ComputedFlexContainerInfo.
static void CreateFlexLineAndFlexItemInfo(
ComputedFlexContainerInfo& aContainerInfo,
const nsTArray<FlexLine>& aLines);
static void ComputeFlexDirections(ComputedFlexContainerInfo& aContainerInfo,
const FlexboxAxisTracker& aAxisTracker);
static void UpdateFlexLineAndItemInfo(
ComputedFlexContainerInfo& aContainerInfo,
const nsTArray<FlexLine>& aLines);
#ifdef DEBUG
void SanityCheckAnonymousFlexItems() const;
#endif // DEBUG
* Returns a new FlexItem for the given child frame, directly constructed at
* the end of aLine. Guaranteed to return non-null.
* Before returning, this method also processes the FlexItem to resolve its
* flex basis (including e.g. auto-height) as well as to resolve
* "min-height:auto", via ResolveAutoFlexBasisAndMinSize(). (Basically, the
* returned FlexItem will be ready to participate in the "Resolve the
* Flexible Lengths" step of the Flex Layout Algorithm.)
* Note that this method **does not** update aLine's main-size bookkeeping to
* account for the newly-constructed flex item. The caller is responsible for
* determining whether this line is a good fit for the new item. If so,
* updating aLine's bookkeeping (via FlexLine::AddLastItemToMainSizeTotals),
* or moving the new item to a new line otherwise.
FlexItem* GenerateFlexItemForChild(
FlexLine& aLine, nsIFrame* aChildFrame,
const ReflowInput& aParentReflowInput,
const FlexboxAxisTracker& aAxisTracker,
const nscoord aTentativeContentBoxCrossSize, bool aHasLineClampEllipsis);
* This method looks up cached block-axis measurements for a flex item, or
* does a measuring reflow and caches those measurements.
* This avoids exponential reflows - see the comment above the
* CachedBAxisMeasurement struct.
const CachedBAxisMeasurement& MeasureBSizeForFlexItem(
FlexItem& aItem, ReflowInput& aChildReflowInput);
* This method performs a "measuring" reflow to get the content BSize of
* aFlexItem.Frame() (treating it as if it had a computed BSize of "auto"),
* and returns the resulting BSize measurement.
* (Helper for ResolveAutoFlexBasisAndMinSize().)
nscoord MeasureFlexItemContentBSize(FlexItem& aFlexItem,
bool aForceBResizeForMeasuringReflow,
bool aHasLineClampEllipsis,
const ReflowInput& aParentReflowInput);
* This method resolves an "auto" flex-basis and/or min-main-size value
* on aFlexItem, if needed.
* (Helper for GenerateFlexItemForChild().)
void ResolveAutoFlexBasisAndMinSize(FlexItem& aFlexItem,
const ReflowInput& aItemReflowInput,
const FlexboxAxisTracker& aAxisTracker,
bool aHasLineClampEllipsis);
* Returns true if "this" is the nsFlexContainerFrame for a -moz-box or
* a -moz-inline-box -- these boxes have special behavior for flex items with
* "visibility:collapse".
* @param aFlexStyleDisp This frame's StyleDisplay(). (Just an optimization to
* avoid repeated lookup; some callers already have it.)
* @return true if "this" is the nsFlexContainerFrame for a -moz-{inline}box.
bool ShouldUseMozBoxCollapseBehavior(const nsStyleDisplay* aFlexStyleDisp);
* This method:
* - Creates FlexItems for all of our child frames (except placeholders).
* - Groups those FlexItems into FlexLines.
* - Returns those FlexLines in the outparam |aLines|.
* This corresponds to "Collect flex items into flex lines" step in the spec.
* For any child frames which are placeholders, this method will instead just
* append that child to the outparam |aPlaceholders| for separate handling.
* (Absolutely positioned children of a flex container are *not* flex items.)
void GenerateFlexLines(const ReflowInput& aReflowInput,
const nscoord aTentativeContentBoxMainSize,
const nscoord aTentativeContentBoxCrossSize,
const nsTArray<StrutInfo>& aStruts,
const FlexboxAxisTracker& aAxisTracker,
nscoord aMainGapSize, bool aHasLineClampEllipsis,
nsTArray<nsIFrame*>& aPlaceholders,
nsTArray<FlexLine>& aLines);
* Generates and returns a FlexLayoutResult that contains the FlexLines and
* some sizing metrics that should be used to lay out a particular flex
* container continuation (i.e. don't call this on the first-in-flow).
FlexLayoutResult GenerateFlexLayoutResult();
* Resolves the content-box main-size of a flex container frame,
* primarily based on:
* - the "tentative" main size, taken from the reflow input ("tentative"
* because it may be unconstrained or may run off the page).
* - the sizes of our lines of flex items.
* We assume the available block-size is always *unconstrained* because this
* is called only in flex algorithm to measure the flex container's size
* without regards to pagination.
* Guaranteed to return a definite length, i.e. not NS_UNCONSTRAINEDSIZE,
* aside from cases with huge lengths which happen to compute to that value.
* This corresponds to "Determine the main size of the flex container" step in
* (Note: This function should be structurally similar to
* ComputeCrossSize().)
nscoord ComputeMainSize(const ReflowInput& aReflowInput,
const FlexboxAxisTracker& aAxisTracker,
const nscoord aTentativeContentBoxMainSize,
nsTArray<FlexLine>& aLines) const;
nscoord ComputeCrossSize(const ReflowInput& aReflowInput,
const FlexboxAxisTracker& aAxisTracker,
const nscoord aTentativeContentBoxCrossSize,
nscoord aSumLineCrossSizes, bool* aIsDefinite) const;
* Compute the size of the available space that we'll give to our children to
* reflow into. In particular, compute the available size that we would give
* to a hypothetical child placed at the IStart/BStart corner of this flex
* container's content-box.
* @param aReflowInput the flex container's reflow input.
* @param aBorderPadding the border and padding of this frame with the
* assumption that this is the last fragment.
* @return the size of the available space for our children to reflow into.
mozilla::LogicalSize ComputeAvailableSizeForItems(
const ReflowInput& aReflowInput,
const mozilla::LogicalMargin& aBorderPadding) const;
void SizeItemInCrossAxis(ReflowInput& aChildReflowInput, FlexItem& aItem);
* This method computes the metrics to be reported via the flex container's
* ReflowOutput & nsReflowStatus output parameters in Reflow().
* @param aContentBoxSize the final content-box size for the flex container as
* a whole, converted from the flex container's
* main/cross sizes. The main/cross sizes are computed
* by DoFlexLayout() if this frame is the
* first-in-flow, or are the stored ones in
* SharedFlexData if this frame is a not the
* first-in-flow.
* @param aBorderPadding the border and padding for this frame (possibly with
* some sides skipped as-appropriate, if we're in a
* continuation chain).
* @param aConsumedBSize the sum of our content-box block-size consumed by our
* prev-in-flows.
* @param aMayNeedNextInFlow true if we may need a next-in-flow because our
* effective content-box block-size exceeds the
* available block-size.
* @param aMaxBlockEndEdgeOfChildren the maximum block-end edge of the
* children of this fragment in this frame's
* coordinate space (as returned by
* ReflowChildren()).
* @param aAnyChildIncomplete true if any child being reflowed is incomplete;
* false otherwise (as returned by
* ReflowChildren()).
* @param aFlexContainerAscent the flex container's ascent, if one has been
* determined from its children. (If there are no
* children, pass nscoord_MIN to synthesize a
* value from the flex container itself).
void PopulateReflowOutput(
ReflowOutput& aReflowOutput, const ReflowInput& aReflowInput,
nsReflowStatus& aStatus, const mozilla::LogicalSize& aContentBoxSize,
const mozilla::LogicalMargin& aBorderPadding,
const nscoord aConsumedBSize, const bool aMayNeedNextInFlow,
const nscoord aMaxBlockEndEdgeOfChildren, const bool aAnyChildIncomplete,
nscoord aFlexContainerAscent, nsTArray<FlexLine>& aLines,
const FlexboxAxisTracker& aAxisTracker);
* Perform a final Reflow for our child frames.
* @param aContainerSize this frame's tentative physical border-box size, used
* only for logical to physical coordinate conversion.
* @param aAvailableSizeForItems the size of the available space for our
* children to reflow into.
* @param aBorderPadding the border and padding for this frame (possibly with
* some sides skipped as-appropriate, if we're in a
* continuation chain).
* @param aSumOfPrevInFlowsChildrenBlockSize See the comment for
* SumOfChildrenBlockSizeProperty.
* @param aFlr the result returned by DoFlexLayout.
* Note: aFlr is mostly an "input" parameter, but we use
* aFlr.mAscent an "in/out" parameter; it's initially the
* "tentative" flex container ascent computed in DoFlexLayout; or,
* nscoord_MIN if the ascent hasn't been established yet. If the
* latter, this will be updated with an ascent derived from the
* first flex item (if there are any flex items).
* @return nscoord the maximum block-end edge of children of this fragment in
* flex container's coordinate space.
* @return bool true if any child being reflowed is incomplete; false
* otherwise.
std::tuple<nscoord, bool> ReflowChildren(
const ReflowInput& aReflowInput, const nsSize& aContainerSize,
const mozilla::LogicalSize& aAvailableSizeForItems,
const mozilla::LogicalMargin& aBorderPadding,
const nscoord aSumOfPrevInFlowsChildrenBlockSize,
const FlexboxAxisTracker& aAxisTracker, bool aHasLineClampEllipsis,
FlexLayoutResult& aFlr);
* Moves the given flex item's frame to the given LogicalPosition (modulo any
* relative positioning).
* This can be used in cases where we've already done a "measuring reflow"
* for the flex item at the correct size, and hence can skip its final reflow
* (but still need to move it to the right final position).
* @param aItem The flex item whose frame should be moved.
* @param aFramePos The position where the flex item's frame should
* be placed. (pre-relative positioning)
* @param aContainerSize The flex container's size (required by some methods
* that we call, to interpret aFramePos correctly).
void MoveFlexItemToFinalPosition(const FlexItem& aItem,
mozilla::LogicalPoint& aFramePos,
const nsSize& aContainerSize);
* Helper-function to reflow a child frame, at its final position determined
* by flex layout.
* @param aAxisTracker A FlexboxAxisTracker with the flex container's axes.
* @param aReflowInput The flex container's reflow input.
* @param aItem The flex item to be reflowed.
* @param aFramePos The position where the flex item's frame should
* be placed. (pre-relative positioning)
* @param aAvailableSize The available size to reflow the child frame (in the
* child frame's writing-mode).
* @param aContainerSize The flex container's size (required by some methods
* that we call, to interpret aFramePos correctly).
* @return the child frame's reflow status.
nsReflowStatus ReflowFlexItem(const FlexboxAxisTracker& aAxisTracker,
const ReflowInput& aReflowInput,
const FlexItem& aItem,
mozilla::LogicalPoint& aFramePos,
const mozilla::LogicalSize& aAvailableSize,
const nsSize& aContainerSize,
bool aHasLineClampEllipsis);
* Helper-function to perform a "dummy reflow" on all our nsPlaceholderFrame
* children, at the container's content-box origin.
* This doesn't actually represent the static position of the placeholders'
* out-of-flow (OOF) frames -- we can't compute that until we've reflowed the
* OOF, because (depending on the CSS Align properties) the static position
* may be influenced by the OOF's size. So for now, we just co-opt the
* placeholder to store the flex container's logical content-box origin, and
* we defer to nsAbsoluteContainingBlock to determine the OOF's actual static
* position (using this origin, the OOF's size, and the CSS Align
* properties).
* @param aReflowInput The flex container's reflow input.
* @param aPlaceholders An array of all the flex container's
* nsPlaceholderFrame children.
* @param aContentBoxOrigin The flex container's logical content-box
* origin (in its own coordinate space).
* @param aContainerSize The flex container's size (required by some
* reflow methods to interpret positions correctly).
void ReflowPlaceholders(const ReflowInput& aReflowInput,
nsTArray<nsIFrame*>& aPlaceholders,
const mozilla::LogicalPoint& aContentBoxOrigin,
const nsSize& aContainerSize);
* Helper for GetMinISize / GetPrefISize.
nscoord IntrinsicISize(gfxContext* aRenderingContext,
mozilla::IntrinsicISizeType aType);
* Cached values to optimize GetMinISize/GetPrefISize.
nscoord mCachedPrefISize = NS_INTRINSIC_ISIZE_UNKNOWN;
nscoord mBaselineFromLastReflow = NS_INTRINSIC_ISIZE_UNKNOWN;
// Note: the last baseline is a distance from our border-box end edge.
nscoord mLastBaselineFromLastReflow = NS_INTRINSIC_ISIZE_UNKNOWN;
#endif /* nsFlexContainerFrame_h___ */