Move rendering/RenderGrid to layout/LayoutGrid

Source/core/rendering/RenderGrid.cpp

-/*
- * Copyright (C) 2011 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "config.h"
-#include "core/rendering/RenderGrid.h"
-
-#include "core/layout/Layer.h"
-#include "core/layout/TextAutosizer.h"
-#include "core/layout/style/GridCoordinate.h"
-#include "core/layout/style/LayoutStyle.h"
-#include "core/paint/GridPainter.h"
-#include "core/rendering/RenderView.h"
-#include "platform/LengthFunctions.h"
-
-namespace blink {
-
-static const int infinity = -1;
-
-class GridTrack {
-public:
-    GridTrack()
-        : m_baseSize(0)
-        , m_growthLimit(0)
-        , m_plannedIncrease(0)
-    {
-    }
-
-    const LayoutUnit& baseSize() const
-    {
-        ASSERT(isGrowthLimitBiggerThanBaseSize());
-        return m_baseSize;
-    }
-
-    const LayoutUnit& growthLimit() const
-    {
-        ASSERT(isGrowthLimitBiggerThanBaseSize());
-        return m_growthLimit;
-    }
-
-    void setBaseSize(LayoutUnit baseSize)
-    {
-        m_baseSize = baseSize;
-        ensureGrowthLimitIsBiggerThanBaseSize();
-    }
-
-    void setGrowthLimit(LayoutUnit growthLimit)
-    {
-        m_growthLimit = growthLimit;
-        ensureGrowthLimitIsBiggerThanBaseSize();
-    }
-
-    void growBaseSize(LayoutUnit growth)
-    {
-        ASSERT(growth >= 0);
-        m_baseSize += growth;
-        ensureGrowthLimitIsBiggerThanBaseSize();
-    }
-
-    void growGrowthLimit(LayoutUnit growth)
-    {
-        ASSERT(growth >= 0);
-        if (m_growthLimit == infinity)
-            m_growthLimit = m_baseSize + growth;
-        else
-            m_growthLimit += growth;
-
-        ASSERT(m_growthLimit >= m_baseSize);
-    }
-
-    bool growthLimitIsInfinite() const
-    {
-        return m_growthLimit == infinity;
-    }
-
-    const LayoutUnit& growthLimitIfNotInfinite() const
-    {
-        ASSERT(isGrowthLimitBiggerThanBaseSize());
-        return (m_growthLimit == infinity) ? m_baseSize : m_growthLimit;
-    }
-
-    const LayoutUnit& plannedIncrease() const { return m_plannedIncrease; }
-
-    void growPlannedIncrease(const LayoutUnit& plannedIncrease)
-    {
-        ASSERT(plannedIncrease >= 0);
-        m_plannedIncrease += plannedIncrease;
-    }
-
-    void updateFromPlannedIncrease(RenderGrid::AccumulatorGrowFunction trackGrowthFunction)
-    {
-        if (m_plannedIncrease == 0)
-            return;
-
-        (this->*trackGrowthFunction)(m_plannedIncrease);
-        m_plannedIncrease = 0;
-    }
-
-private:
-    bool isGrowthLimitBiggerThanBaseSize() const { return growthLimitIsInfinite() || m_growthLimit >= m_baseSize; }
-
-    void ensureGrowthLimitIsBiggerThanBaseSize()
-    {
-        if (m_growthLimit != infinity && m_growthLimit < m_baseSize)
-            m_growthLimit = m_baseSize;
-    }
-
-    LayoutUnit m_baseSize;
-    LayoutUnit m_growthLimit;
-    LayoutUnit m_plannedIncrease;
-};
-
-struct GridTrackForNormalization {
-    GridTrackForNormalization(const GridTrack& track, double flex)
-        : m_track(&track)
-        , m_flex(flex)
-        , m_normalizedFlexValue(track.baseSize() / flex)
-    {
-    }
-
-    // Required by std::sort.
-    GridTrackForNormalization& operator=(const GridTrackForNormalization& o)
-    {
-        m_track = o.m_track;
-        m_flex = o.m_flex;
-        m_normalizedFlexValue = o.m_normalizedFlexValue;
-        return *this;
-    }
-
-    const GridTrack* m_track;
-    double m_flex;
-    LayoutUnit m_normalizedFlexValue;
-};
-
-class RenderGrid::GridIterator {
-    WTF_MAKE_NONCOPYABLE(GridIterator);
-public:
-    // |direction| is the direction that is fixed to |fixedTrackIndex| so e.g
-    // GridIterator(m_grid, ForColumns, 1) will walk over the rows of the 2nd column.
-    GridIterator(const GridRepresentation& grid, GridTrackSizingDirection direction, size_t fixedTrackIndex, size_t varyingTrackIndex = 0)
-        : m_grid(grid)
-        , m_direction(direction)
-        , m_rowIndex((direction == ForColumns) ? varyingTrackIndex : fixedTrackIndex)
-        , m_columnIndex((direction == ForColumns) ? fixedTrackIndex : varyingTrackIndex)
-        , m_childIndex(0)
-    {
-        ASSERT(m_rowIndex < m_grid.size());
-        ASSERT(m_columnIndex < m_grid[0].size());
-    }
-
-    LayoutBox* nextGridItem()
-    {
-        ASSERT(!m_grid.isEmpty());
-
-        size_t& varyingTrackIndex = (m_direction == ForColumns) ? m_rowIndex : m_columnIndex;
-        const size_t endOfVaryingTrackIndex = (m_direction == ForColumns) ? m_grid.size() : m_grid[0].size();
-        for (; varyingTrackIndex < endOfVaryingTrackIndex; ++varyingTrackIndex) {
-            const GridCell& children = m_grid[m_rowIndex][m_columnIndex];
-            if (m_childIndex < children.size())
-                return children[m_childIndex++];
-
-            m_childIndex = 0;
-        }
-        return 0;
-    }
-
-    bool checkEmptyCells(size_t rowSpan, size_t columnSpan) const
-    {
-        // Ignore cells outside current grid as we will grow it later if needed.
-        size_t maxRows = std::min(m_rowIndex + rowSpan, m_grid.size());
-        size_t maxColumns = std::min(m_columnIndex + columnSpan, m_grid[0].size());
-
-        // This adds a O(N^2) behavior that shouldn't be a big deal as we expect spanning areas to be small.
-        for (size_t row = m_rowIndex; row < maxRows; ++row) {
-            for (size_t column = m_columnIndex; column < maxColumns; ++column) {
-                const GridCell& children = m_grid[row][column];
-                if (!children.isEmpty())
-                    return false;
-            }
-        }
-
-        return true;
-    }
-
-    PassOwnPtr<GridCoordinate> nextEmptyGridArea(size_t fixedTrackSpan, size_t varyingTrackSpan)
-    {
-        ASSERT(!m_grid.isEmpty());
-        ASSERT(fixedTrackSpan >= 1 && varyingTrackSpan >= 1);
-
-        size_t rowSpan = (m_direction == ForColumns) ? varyingTrackSpan : fixedTrackSpan;
-        size_t columnSpan = (m_direction == ForColumns) ? fixedTrackSpan : varyingTrackSpan;
-
-        size_t& varyingTrackIndex = (m_direction == ForColumns) ? m_rowIndex : m_columnIndex;
-        const size_t endOfVaryingTrackIndex = (m_direction == ForColumns) ? m_grid.size() : m_grid[0].size();
-        for (; varyingTrackIndex < endOfVaryingTrackIndex; ++varyingTrackIndex) {
-            if (checkEmptyCells(rowSpan, columnSpan)) {
-                OwnPtr<GridCoordinate> result = adoptPtr(new GridCoordinate(GridSpan(m_rowIndex, m_rowIndex + rowSpan - 1), GridSpan(m_columnIndex, m_columnIndex + columnSpan - 1)));
-                // Advance the iterator to avoid an infinite loop where we would return the same grid area over and over.
-                ++varyingTrackIndex;
-                return result.release();
-            }
-        }
-        return nullptr;
-    }
-
-private:
-    const GridRepresentation& m_grid;
-    GridTrackSizingDirection m_direction;
-    size_t m_rowIndex;
-    size_t m_columnIndex;
-    size_t m_childIndex;
-};
-
-struct RenderGrid::GridSizingData {
-    WTF_MAKE_NONCOPYABLE(GridSizingData);
-    STACK_ALLOCATED();
-public:
-    GridSizingData(size_t gridColumnCount, size_t gridRowCount)
-        : columnTracks(gridColumnCount)
-        , rowTracks(gridRowCount)
-    {
-    }
-
-    Vector<GridTrack> columnTracks;
-    Vector<GridTrack> rowTracks;
-    Vector<size_t> contentSizedTracksIndex;
-
-    // Performance optimization: hold onto these Vectors until the end of Layout to avoid repeated malloc / free.
-    Vector<GridTrack*> filteredTracks;
-    Vector<GridItemWithSpan> itemsSortedByIncreasingSpan;
-    Vector<GridTrack*> growBeyondGrowthLimitsTracks;
-};
-
-RenderGrid::RenderGrid(Element* element)
-    : RenderBlock(element)
-    , m_gridIsDirty(true)
-    , m_orderIterator(this)
-{
-    ASSERT(!childrenInline());
-}
-
-RenderGrid::~RenderGrid()
-{
-}
-
-void RenderGrid::addChild(LayoutObject* newChild, LayoutObject* beforeChild)
-{
-    RenderBlock::addChild(newChild, beforeChild);
-
-    if (gridIsDirty())
-        return;
-
-    // The grid needs to be recomputed as it might contain auto-placed items that will change their position.
-    dirtyGrid();
-    return;
-}
-
-void RenderGrid::removeChild(LayoutObject* child)
-{
-    RenderBlock::removeChild(child);
-
-    if (gridIsDirty())
-        return;
-
-    // The grid needs to be recomputed as it might contain auto-placed items that will change their position.
-    dirtyGrid();
-    return;
-}
-
-void RenderGrid::styleDidChange(StyleDifference diff, const LayoutStyle* oldStyle)
-{
-    RenderBlock::styleDidChange(diff, oldStyle);
-    if (!oldStyle)
-        return;
-
-    // FIXME: The following checks could be narrowed down if we kept track of which type of grid items we have:
-    // - explicit grid size changes impact negative explicitely positioned and auto-placed grid items.
-    // - named grid lines only impact grid items with named grid lines.
-    // - auto-flow changes only impacts auto-placed children.
-
-    if (explicitGridDidResize(*oldStyle)
-        || namedGridLinesDefinitionDidChange(*oldStyle)
-        || oldStyle->gridAutoFlow() != styleRef().gridAutoFlow())
-        dirtyGrid();
-}
-
-bool RenderGrid::explicitGridDidResize(const LayoutStyle& oldStyle) const
-{
-    return oldStyle.gridTemplateColumns().size() != styleRef().gridTemplateColumns().size()
-        || oldStyle.gridTemplateRows().size() != styleRef().gridTemplateRows().size();
-}
-
-bool RenderGrid::namedGridLinesDefinitionDidChange(const LayoutStyle& oldStyle) const
-{
-    return oldStyle.namedGridRowLines() != styleRef().namedGridRowLines()
-        || oldStyle.namedGridColumnLines() != styleRef().namedGridColumnLines();
-}
-
-void RenderGrid::layoutBlock(bool relayoutChildren)
-{
-    ASSERT(needsLayout());
-
-    if (!relayoutChildren && simplifiedLayout())
-        return;
-
-    // FIXME: Much of this method is boiler plate that matches LayoutBox::layoutBlock and Render*FlexibleBox::layoutBlock.
-    // It would be nice to refactor some of the duplicate code.
-    {
-        // LayoutState needs this deliberate scope to pop before updating scroll information (which
-        // may trigger relayout).
-        LayoutState state(*this, locationOffset());
-
-        LayoutSize previousSize = size();
-
-        setLogicalHeight(0);
-        updateLogicalWidth();
-
-        TextAutosizer::LayoutScope textAutosizerLayoutScope(this);
-
-        layoutGridItems();
-
-        LayoutUnit oldClientAfterEdge = clientLogicalBottom();
-        updateLogicalHeight();
-
-        if (size() != previousSize)
-            relayoutChildren = true;
-
-        layoutPositionedObjects(relayoutChildren || isDocumentElement());
-
-        computeOverflow(oldClientAfterEdge);
-    }
-
-    updateLayerTransformAfterLayout();
-
-    // Update our scroll information if we're overflow:auto/scroll/hidden now that we know if
-    // we overflow or not.
-    if (hasOverflowClip())
-        layer()->scrollableArea()->updateAfterLayout();
-
-    clearNeedsLayout();
-}
-
-void RenderGrid::computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const
-{
-    const_cast<RenderGrid*>(this)->placeItemsOnGrid();
-
-    GridSizingData sizingData(gridColumnCount(), gridRowCount());
-    LayoutUnit availableLogicalSpace = 0;
-    const_cast<RenderGrid*>(this)->computeUsedBreadthOfGridTracks(ForColumns, sizingData, availableLogicalSpace);
-
-    for (const auto& column : sizingData.columnTracks) {
-        const LayoutUnit& minTrackBreadth = column.baseSize();
-        const LayoutUnit& maxTrackBreadth = column.growthLimit();
-
-        minLogicalWidth += minTrackBreadth;
-        maxLogicalWidth += maxTrackBreadth;
-
-        LayoutUnit scrollbarWidth = intrinsicScrollbarLogicalWidth();
-        maxLogicalWidth += scrollbarWidth;
-        minLogicalWidth += scrollbarWidth;
-    }
-}
-
-void RenderGrid::computePreferredLogicalWidths()
-{
-    ASSERT(preferredLogicalWidthsDirty());
-
-    m_minPreferredLogicalWidth = 0;
-    m_maxPreferredLogicalWidth = 0;
-
-    // FIXME: We don't take our own logical width into account. Once we do, we need to make sure
-    // we apply (and test the interaction with) min-width / max-width.
-
-    computeIntrinsicLogicalWidths(m_minPreferredLogicalWidth, m_maxPreferredLogicalWidth);
-
-    LayoutUnit borderAndPaddingInInlineDirection = borderAndPaddingLogicalWidth();
-    m_minPreferredLogicalWidth += borderAndPaddingInInlineDirection;
-    m_maxPreferredLogicalWidth += borderAndPaddingInInlineDirection;
-
-    clearPreferredLogicalWidthsDirty();
-}
-
-void RenderGrid::computeUsedBreadthOfGridTracks(GridTrackSizingDirection direction, GridSizingData& sizingData)
-{
-    LayoutUnit availableLogicalSpace = (direction == ForColumns) ? availableLogicalWidth() : availableLogicalHeight(IncludeMarginBorderPadding);
-    computeUsedBreadthOfGridTracks(direction, sizingData, availableLogicalSpace);
-}
-
-bool RenderGrid::gridElementIsShrinkToFit()
-{
-    return isFloatingOrOutOfFlowPositioned();
-}
-
-void RenderGrid::computeUsedBreadthOfGridTracks(GridTrackSizingDirection direction, GridSizingData& sizingData, LayoutUnit& freeSpace)
-{
-    const LayoutUnit initialFreeSpace = freeSpace;
-    Vector<GridTrack>& tracks = (direction == ForColumns) ? sizingData.columnTracks : sizingData.rowTracks;
-    Vector<size_t> flexibleSizedTracksIndex;
-    sizingData.contentSizedTracksIndex.shrink(0);
-
-    // 1. Initialize per Grid track variables.
-    for (size_t i = 0; i < tracks.size(); ++i) {
-        GridTrack& track = tracks[i];
-        GridTrackSize trackSize = gridTrackSize(direction, i);
-        const GridLength& minTrackBreadth = trackSize.minTrackBreadth();
-        const GridLength& maxTrackBreadth = trackSize.maxTrackBreadth();
-
-        track.setBaseSize(computeUsedBreadthOfMinLength(direction, minTrackBreadth));
-        track.setGrowthLimit(computeUsedBreadthOfMaxLength(direction, maxTrackBreadth, track.baseSize()));
-
-        if (trackSize.isContentSized())
-            sizingData.contentSizedTracksIndex.append(i);
-        if (trackSize.maxTrackBreadth().isFlex())
-            flexibleSizedTracksIndex.append(i);
-    }
-
-    // 2. Resolve content-based TrackSizingFunctions.
-    if (!sizingData.contentSizedTracksIndex.isEmpty())
-        resolveContentBasedTrackSizingFunctions(direction, sizingData, freeSpace);
-
-    for (const auto& track: tracks) {
-        ASSERT(!track.growthLimitIsInfinite());
-        freeSpace -= track.baseSize();
-    }
-
-    const bool hasUndefinedRemainingSpace = (direction == ForRows) ? style()->logicalHeight().isAuto() : gridElementIsShrinkToFit();
-
-    if (!hasUndefinedRemainingSpace && freeSpace <= 0)
-        return;
-
-    // 3. Grow all Grid tracks in GridTracks from their baseSize up to their growthLimit value until freeSpace is exhausted.
-    const size_t tracksSize = tracks.size();
-    if (!hasUndefinedRemainingSpace) {
-        Vector<GridTrack*> tracksForDistribution(tracksSize);
-        for (size_t i = 0; i < tracksSize; ++i)
-            tracksForDistribution[i] = tracks.data() + i;
-
-        distributeSpaceToTracks(tracksForDistribution, nullptr, &GridTrack::baseSize, &GridTrack::growBaseSize, sizingData, freeSpace);
-    } else {
-        for (auto& track : tracks)
-            track.setBaseSize(track.growthLimit());
-    }
-
-    if (flexibleSizedTracksIndex.isEmpty())
-        return;
-
-    // 4. Grow all Grid tracks having a fraction as the MaxTrackSizingFunction.
-    double normalizedFractionBreadth = 0;
-    if (!hasUndefinedRemainingSpace) {
-        normalizedFractionBreadth = computeNormalizedFractionBreadth(tracks, GridSpan(0, tracks.size() - 1), direction, initialFreeSpace);
-    } else {
-        for (const auto& trackIndex : flexibleSizedTracksIndex) {
-            GridTrackSize trackSize = gridTrackSize(direction, trackIndex);
-            normalizedFractionBreadth = std::max(normalizedFractionBreadth, tracks[trackIndex].baseSize() / trackSize.maxTrackBreadth().flex());
-        }
-
-        for (size_t i = 0; i < flexibleSizedTracksIndex.size(); ++i) {
-            GridIterator iterator(m_grid, direction, flexibleSizedTracksIndex[i]);
-            while (LayoutBox* gridItem = iterator.nextGridItem()) {
-                const GridCoordinate coordinate = cachedGridCoordinate(*gridItem);
-                const GridSpan span = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
-
-                // Do not include already processed items.
-                if (i > 0 && span.resolvedInitialPosition.toInt() <= flexibleSizedTracksIndex[i - 1])
-                    continue;
-
-                double itemNormalizedFlexBreadth = computeNormalizedFractionBreadth(tracks, span, direction, maxContentForChild(*gridItem, direction, sizingData.columnTracks));
-                normalizedFractionBreadth = std::max(normalizedFractionBreadth, itemNormalizedFlexBreadth);
-            }
-        }
-    }
-
-    for (const auto& trackIndex : flexibleSizedTracksIndex) {
-        GridTrackSize trackSize = gridTrackSize(direction, trackIndex);
-
-        LayoutUnit baseSize = std::max<LayoutUnit>(tracks[trackIndex].baseSize(), normalizedFractionBreadth * trackSize.maxTrackBreadth().flex());
-        tracks[trackIndex].setBaseSize(baseSize);
-        freeSpace -= baseSize;
-    }
-
-    // FIXME: Should ASSERT flexible tracks exhaust the freeSpace ? (see issue 739613002).
-}
-
-LayoutUnit RenderGrid::computeUsedBreadthOfMinLength(GridTrackSizingDirection direction, const GridLength& gridLength) const
-{
-    if (gridLength.isFlex())
-        return 0;
-
-    const Length& trackLength = gridLength.length();
-    ASSERT(!trackLength.isAuto());
-    if (trackLength.isSpecified())
-        return computeUsedBreadthOfSpecifiedLength(direction, trackLength);
-
-    ASSERT(trackLength.isMinContent() || trackLength.isMaxContent());
-    return 0;
-}
-
-LayoutUnit RenderGrid::computeUsedBreadthOfMaxLength(GridTrackSizingDirection direction, const GridLength& gridLength, LayoutUnit usedBreadth) const
-{
-    if (gridLength.isFlex())
-        return usedBreadth;
-
-    const Length& trackLength = gridLength.length();
-    ASSERT(!trackLength.isAuto());
-    if (trackLength.isSpecified()) {
-        LayoutUnit computedBreadth = computeUsedBreadthOfSpecifiedLength(direction, trackLength);
-        ASSERT(computedBreadth != infinity);
-        return computedBreadth;
-    }
-
-    ASSERT(trackLength.isMinContent() || trackLength.isMaxContent());
-    return infinity;
-}
-
-LayoutUnit RenderGrid::computeUsedBreadthOfSpecifiedLength(GridTrackSizingDirection direction, const Length& trackLength) const
-{
-    ASSERT(trackLength.isSpecified());
-    // FIXME: The -1 here should be replaced by whatever the intrinsic height of the grid is.
-    return valueForLength(trackLength, direction == ForColumns ? logicalWidth() : computeContentLogicalHeight(style()->logicalHeight(), -1));
-}
-
-static bool sortByGridNormalizedFlexValue(const GridTrackForNormalization& track1, const GridTrackForNormalization& track2)
-{
-    return track1.m_normalizedFlexValue < track2.m_normalizedFlexValue;
-}
-
-double RenderGrid::computeNormalizedFractionBreadth(Vector<GridTrack>& tracks, const GridSpan& tracksSpan, GridTrackSizingDirection direction, LayoutUnit spaceToFill) const
-{
-    LayoutUnit allocatedSpace;
-    Vector<GridTrackForNormalization> tracksForNormalization;
-    for (const auto& resolvedPosition : tracksSpan) {
-        GridTrack& track = tracks[resolvedPosition.toInt()];
-        allocatedSpace += track.baseSize();
-
-        GridTrackSize trackSize = gridTrackSize(direction, resolvedPosition.toInt());
-        if (!trackSize.maxTrackBreadth().isFlex())
-            continue;
-
-        tracksForNormalization.append(GridTrackForNormalization(track, trackSize.maxTrackBreadth().flex()));
-    }
-
-    // The function is not called if we don't have <flex> grid tracks
-    ASSERT(!tracksForNormalization.isEmpty());
-
-    std::sort(tracksForNormalization.begin(), tracksForNormalization.end(), sortByGridNormalizedFlexValue);
-
-    // These values work together: as we walk over our grid tracks, we increase fractionValueBasedOnGridItemsRatio
-    // to match a grid track's usedBreadth to <flex> ratio until the total fractions sized grid tracks wouldn't
-    // fit into availableLogicalSpaceIgnoringFractionTracks.
-    double accumulatedFractions = 0;
-    LayoutUnit fractionValueBasedOnGridItemsRatio = 0;
-    LayoutUnit availableLogicalSpaceIgnoringFractionTracks = spaceToFill - allocatedSpace;
-
-    for (const auto& track : tracksForNormalization) {
-        if (track.m_normalizedFlexValue > fractionValueBasedOnGridItemsRatio) {
-            // If the normalized flex value (we ordered |tracksForNormalization| by increasing normalized flex value)
-            // will make us overflow our container, then stop. We have the previous step's ratio is the best fit.
-            if (track.m_normalizedFlexValue * accumulatedFractions > availableLogicalSpaceIgnoringFractionTracks)
-                break;
-
-            fractionValueBasedOnGridItemsRatio = track.m_normalizedFlexValue;
-        }
-
-        accumulatedFractions += track.m_flex;
-        // This item was processed so we re-add its used breadth to the available space to accurately count the remaining space.
-        availableLogicalSpaceIgnoringFractionTracks += track.m_track->baseSize();
-    }
-
-    return availableLogicalSpaceIgnoringFractionTracks / accumulatedFractions;
-}
-
-bool RenderGrid::hasDefiniteLogicalSize(GridTrackSizingDirection direction) const
-{
-    return (direction == ForRows) ? hasDefiniteLogicalHeight() : hasDefiniteLogicalWidth();
-}
-
-GridTrackSize RenderGrid::gridTrackSize(GridTrackSizingDirection direction, size_t i) const
-{
-    bool isForColumns = direction == ForColumns;
-    const Vector<GridTrackSize>& trackStyles = isForColumns ? style()->gridTemplateColumns() : style()->gridTemplateRows();
-    const GridTrackSize& trackSize = (i >= trackStyles.size()) ? (isForColumns ? style()->gridAutoColumns() : style()->gridAutoRows()) : trackStyles[i];
-
-    // If the logical width/height of the grid container is indefinite, percentage values are treated as <auto> (or in
-    // the case of minmax() as min-content for the first position and max-content for the second).
-    if (!hasDefiniteLogicalSize(direction)) {
-        const GridLength& oldMinTrackBreadth = trackSize.minTrackBreadth();
-        const GridLength& oldMaxTrackBreadth = trackSize.maxTrackBreadth();
-        return GridTrackSize(oldMinTrackBreadth.isPercentage() ? Length(MinContent) : oldMinTrackBreadth, oldMaxTrackBreadth.isPercentage() ? Length(MaxContent) : oldMaxTrackBreadth);
-    }
-
-    return trackSize;
-}
-
-LayoutUnit RenderGrid::logicalHeightForChild(LayoutBox& child, Vector<GridTrack>& columnTracks)
-{
-    SubtreeLayoutScope layoutScope(child);
-    LayoutUnit oldOverrideContainingBlockContentLogicalWidth = child.hasOverrideContainingBlockLogicalWidth() ? child.overrideContainingBlockContentLogicalWidth() : LayoutUnit();
-    LayoutUnit overrideContainingBlockContentLogicalWidth = gridAreaBreadthForChild(child, ForColumns, columnTracks);
-    if (child.style()->logicalHeight().isPercent() || oldOverrideContainingBlockContentLogicalWidth != overrideContainingBlockContentLogicalWidth)
-        layoutScope.setNeedsLayout(&child);
-
-    child.clearOverrideLogicalContentHeight();
-
-    child.setOverrideContainingBlockContentLogicalWidth(overrideContainingBlockContentLogicalWidth);
-    // If |child| has a percentage logical height, we shouldn't let it override its intrinsic height, which is
-    // what we are interested in here. Thus we need to set the override logical height to -1 (no possible resolution).
-    child.setOverrideContainingBlockContentLogicalHeight(-1);
-    child.layoutIfNeeded();
-    return child.logicalHeight() + child.marginLogicalHeight();
-}
-
-LayoutUnit RenderGrid::minContentForChild(LayoutBox& child, GridTrackSizingDirection direction, Vector<GridTrack>& columnTracks)
-{
-    bool hasOrthogonalWritingMode = child.isHorizontalWritingMode() != isHorizontalWritingMode();
-    // FIXME: Properly support orthogonal writing mode.
-    if (hasOrthogonalWritingMode)
-        return 0;
-
-    if (direction == ForColumns) {
-        // FIXME: It's unclear if we should return the intrinsic width or the preferred width.
-        // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
-        return child.minPreferredLogicalWidth() + marginIntrinsicLogicalWidthForChild(child);
-    }
-
-    return logicalHeightForChild(child, columnTracks);
-}
-
-LayoutUnit RenderGrid::maxContentForChild(LayoutBox& child, GridTrackSizingDirection direction, Vector<GridTrack>& columnTracks)
-{
-    bool hasOrthogonalWritingMode = child.isHorizontalWritingMode() != isHorizontalWritingMode();
-    // FIXME: Properly support orthogonal writing mode.
-    if (hasOrthogonalWritingMode)
-        return LayoutUnit();
-
-    if (direction == ForColumns) {
-        // FIXME: It's unclear if we should return the intrinsic width or the preferred width.
-        // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
-        return child.maxPreferredLogicalWidth() + marginIntrinsicLogicalWidthForChild(child);
-    }
-
-    return logicalHeightForChild(child, columnTracks);
-}
-
-// We're basically using a class instead of a std::pair for two reasons. First of all, accessing gridItem() or
-// coordinate() is much more self-explanatory that using .first or .second members in the pair. Secondly the class
-// allows us to precompute the value of the span, something which is quite convenient for the sorting. Having a
-// std::pair<LayoutBox*, size_t> does not work either because we still need the GridCoordinate so we'd have to add an
-// extra hash lookup for each item at the beginning of RenderGrid::resolveContentBasedTrackSizingFunctionsForItems().
-class GridItemWithSpan {
-public:
-    GridItemWithSpan(LayoutBox& gridItem, const GridCoordinate& coordinate, GridTrackSizingDirection direction)
-        : m_gridItem(&gridItem)
-        , m_coordinate(coordinate)
-    {
-        const GridSpan& span = (direction == ForRows) ? coordinate.rows : coordinate.columns;
-        m_span = span.resolvedFinalPosition.toInt() - span.resolvedInitialPosition.toInt() + 1;
-    }
-
-    LayoutBox& gridItem() const { return *m_gridItem; }
-    GridCoordinate coordinate() const { return m_coordinate; }
-#if ENABLE(ASSERT)
-    size_t span() const { return m_span; }
-#endif
-
-    bool operator<(const GridItemWithSpan other) const { return m_span < other.m_span; }
-
-private:
-    LayoutBox* m_gridItem;
-    GridCoordinate m_coordinate;
-    size_t m_span;
-};
-
-bool RenderGrid::spanningItemCrossesFlexibleSizedTracks(const GridCoordinate& coordinate, GridTrackSizingDirection direction) const
-{
-    const GridResolvedPosition initialTrackPosition = (direction == ForColumns) ? coordinate.columns.resolvedInitialPosition : coordinate.rows.resolvedInitialPosition;
-    const GridResolvedPosition finalTrackPosition = (direction == ForColumns) ? coordinate.columns.resolvedFinalPosition : coordinate.rows.resolvedFinalPosition;
-
-    for (GridResolvedPosition trackPosition = initialTrackPosition; trackPosition <= finalTrackPosition; ++trackPosition) {
-        const GridTrackSize& trackSize = gridTrackSize(direction, trackPosition.toInt());
-        if (trackSize.minTrackBreadth().isFlex() || trackSize.maxTrackBreadth().isFlex())
-            return true;
-    }
-
-    return false;
-}
-
-static inline size_t integerSpanForDirection(const GridCoordinate& coordinate, GridTrackSizingDirection direction)
-{
-    return (direction == ForRows) ? coordinate.rows.integerSpan() : coordinate.columns.integerSpan();
-}
-
-void RenderGrid::resolveContentBasedTrackSizingFunctions(GridTrackSizingDirection direction, GridSizingData& sizingData, LayoutUnit& availableLogicalSpace)
-{
-    sizingData.itemsSortedByIncreasingSpan.shrink(0);
-    HashSet<LayoutBox*> itemsSet;
-    for (const auto& trackIndex : sizingData.contentSizedTracksIndex) {
-        GridIterator iterator(m_grid, direction, trackIndex);
-        GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[trackIndex] : sizingData.rowTracks[trackIndex];
-        while (LayoutBox* gridItem = iterator.nextGridItem()) {
-            if (itemsSet.add(gridItem).isNewEntry) {
-                const GridCoordinate& coordinate = cachedGridCoordinate(*gridItem);
-                if (integerSpanForDirection(coordinate, direction) == 1) {
-                    resolveContentBasedTrackSizingFunctionsForNonSpanningItems(direction, coordinate, *gridItem, track, sizingData.columnTracks);
-                } else if (!spanningItemCrossesFlexibleSizedTracks(coordinate, direction)) {
-                    sizingData.itemsSortedByIncreasingSpan.append(GridItemWithSpan(*gridItem, coordinate, direction));
-                }
-            }
-        }
-    }
-    std::sort(sizingData.itemsSortedByIncreasingSpan.begin(), sizingData.itemsSortedByIncreasingSpan.end());
-
-    Vector<GridItemWithSpan>::iterator end = sizingData.itemsSortedByIncreasingSpan.end();
-    for (Vector<GridItemWithSpan>::iterator it = sizingData.itemsSortedByIncreasingSpan.begin(); it != end; ++it) {
-        GridItemWithSpan itemWithSpan = *it;
-        resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, itemWithSpan, &GridTrackSize::hasMinOrMaxContentMinTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::baseSize, &GridTrack::growBaseSize, &GridTrackSize::hasMinContentMinTrackBreadthAndMinOrMaxContentMaxTrackBreadth);
-        resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, itemWithSpan, &GridTrackSize::hasMaxContentMinTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::baseSize, &GridTrack::growBaseSize, &GridTrackSize::hasMaxContentMinTrackBreadthAndMaxContentMaxTrackBreadth);
-        resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, itemWithSpan, &GridTrackSize::hasMinOrMaxContentMaxTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::growthLimitIfNotInfinite, &GridTrack::growGrowthLimit);
-        resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, itemWithSpan, &GridTrackSize::hasMaxContentMaxTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::growthLimitIfNotInfinite, &GridTrack::growGrowthLimit);
-    }
-
-    for (const auto& trackIndex : sizingData.contentSizedTracksIndex) {
-        GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[trackIndex] : sizingData.rowTracks[trackIndex];
-        if (track.growthLimitIsInfinite())
-            track.setGrowthLimit(track.baseSize());
-    }
-}
-
-void RenderGrid::resolveContentBasedTrackSizingFunctionsForNonSpanningItems(GridTrackSizingDirection direction, const GridCoordinate& coordinate, LayoutBox& gridItem, GridTrack& track, Vector<GridTrack>& columnTracks)
-{
-    const GridResolvedPosition trackPosition = (direction == ForColumns) ? coordinate.columns.resolvedInitialPosition : coordinate.rows.resolvedInitialPosition;
-    GridTrackSize trackSize = gridTrackSize(direction, trackPosition.toInt());
-
-    if (trackSize.hasMinContentMinTrackBreadth())
-        track.setBaseSize(std::max(track.baseSize(), minContentForChild(gridItem, direction, columnTracks)));
-    else if (trackSize.hasMaxContentMinTrackBreadth())
-        track.setBaseSize(std::max(track.baseSize(), maxContentForChild(gridItem, direction, columnTracks)));
-
-    if (trackSize.hasMinContentMaxTrackBreadth())
-        track.setGrowthLimit(std::max(track.growthLimit(), minContentForChild(gridItem, direction, columnTracks)));
-    else if (trackSize.hasMaxContentMaxTrackBreadth())
-        track.setGrowthLimit(std::max(track.growthLimit(), maxContentForChild(gridItem, direction, columnTracks)));
-}
-
-void RenderGrid::resolveContentBasedTrackSizingFunctionsForItems(GridTrackSizingDirection direction, GridSizingData& sizingData, GridItemWithSpan& gridItemWithSpan, FilterFunction filterFunction, SizingFunction sizingFunction, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction, FilterFunction growAboveMaxBreadthFilterFunction)
-{
-    ASSERT(gridItemWithSpan.span() > 1);
-    const GridCoordinate coordinate = gridItemWithSpan.coordinate();
-    const GridSpan& itemSpan = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
-
-    sizingData.growBeyondGrowthLimitsTracks.shrink(0);
-    sizingData.filteredTracks.shrink(0);
-    LayoutUnit spanningTracksSize;
-    for (const auto& trackPosition : itemSpan) {
-        GridTrackSize trackSize = gridTrackSize(direction, trackPosition.toInt());
-        GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[trackPosition.toInt()] : sizingData.rowTracks[trackPosition.toInt()];
-        spanningTracksSize += (track.*trackGetter)();
-        if (!(trackSize.*filterFunction)())
-            continue;
-
-        sizingData.filteredTracks.append(&track);
-
-        if (!growAboveMaxBreadthFilterFunction || (trackSize.*growAboveMaxBreadthFilterFunction)())
-            sizingData.growBeyondGrowthLimitsTracks.append(&track);
-    }
-
-    if (sizingData.filteredTracks.isEmpty())
-        return;
-
-    // Specs mandate to floor extraSpace to 0. Instead we directly avoid the function call in those cases as it will be
-    // a noop in terms of track sizing.
-    LayoutUnit extraSpace = (this->*sizingFunction)(gridItemWithSpan.gridItem(), direction, sizingData.columnTracks) - spanningTracksSize;
-    if (extraSpace > 0) {
-        Vector<GridTrack*>* tracksToGrowBeyondGrowthLimits = sizingData.growBeyondGrowthLimitsTracks.isEmpty() ? &sizingData.filteredTracks : &sizingData.growBeyondGrowthLimitsTracks;
-        distributeSpaceToTracks(sizingData.filteredTracks, tracksToGrowBeyondGrowthLimits, trackGetter, trackGrowthFunction, sizingData, extraSpace);
-    }
-}
-
-static bool sortByGridTrackGrowthPotential(const GridTrack* track1, const GridTrack* track2)
-{
-    // This check ensures that we respect the irreflexivity property of the strict weak ordering required by std::sort
-    // (forall x: NOT x < x).
-    if (track1->growthLimitIsInfinite() && track2->growthLimitIsInfinite())
-        return false;
-
-    if (track1->growthLimitIsInfinite() || track2->growthLimitIsInfinite())
-        return track2->growthLimitIsInfinite();
-
-    return (track1->growthLimit() - track1->baseSize()) < (track2->growthLimit() - track2->baseSize());
-}
-
-void RenderGrid::distributeSpaceToTracks(Vector<GridTrack*>& tracks, const Vector<GridTrack*>* growBeyondGrowthLimitsTracks, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction, GridSizingData& sizingData, LayoutUnit& availableLogicalSpace)
-{
-    ASSERT(availableLogicalSpace > 0);
-    std::sort(tracks.begin(), tracks.end(), sortByGridTrackGrowthPotential);
-
-    size_t tracksSize = tracks.size();
-    for (size_t i = 0; i < tracksSize; ++i) {
-        GridTrack& track = *tracks[i];
-        ASSERT(track.plannedIncrease() == 0);
-        LayoutUnit availableLogicalSpaceShare = availableLogicalSpace / (tracksSize - i);
-        const LayoutUnit& trackBreadth = (track.*trackGetter)();
-        LayoutUnit growthShare = track.growthLimitIsInfinite() ? availableLogicalSpaceShare : std::min(availableLogicalSpaceShare, track.growthLimit() - trackBreadth);
-        // We should never shrink any grid track or else we can't guarantee we abide by our min-sizing function.
-        if (growthShare > 0) {
-            track.growPlannedIncrease(growthShare);
-            availableLogicalSpace -= growthShare;
-        }
-    }
-
-    if (availableLogicalSpace > 0 && growBeyondGrowthLimitsTracks) {
-        size_t tracksGrowingAboveMaxBreadthSize = growBeyondGrowthLimitsTracks->size();
-        for (size_t i = 0; i < tracksGrowingAboveMaxBreadthSize; ++i) {
-            GridTrack* track = growBeyondGrowthLimitsTracks->at(i);
-            LayoutUnit growthShare = availableLogicalSpace / (tracksGrowingAboveMaxBreadthSize - i);
-            track->growPlannedIncrease(growthShare);
-            availableLogicalSpace -= growthShare;
-        }
-    }
-
-    for (auto* track: tracks) {
-        track->updateFromPlannedIncrease(trackGrowthFunction);
-        ASSERT(track->plannedIncrease() == 0);
-    }
-}
-
-#if ENABLE(ASSERT)
-bool RenderGrid::tracksAreWiderThanMinTrackBreadth(GridTrackSizingDirection direction, const Vector<GridTrack>& tracks)
-{
-    for (size_t i = 0; i < tracks.size(); ++i) {
-        GridTrackSize trackSize = gridTrackSize(direction, i);
-        const GridLength& minTrackBreadth = trackSize.minTrackBreadth();
-        if (computeUsedBreadthOfMinLength(direction, minTrackBreadth) > tracks[i].baseSize())
-            return false;
-    }
-    return true;
-}
-#endif
-
-void RenderGrid::ensureGridSize(size_t maximumRowIndex, size_t maximumColumnIndex)
-{
-    const size_t oldRowSize = gridRowCount();
-    if (maximumRowIndex >= oldRowSize) {
-        m_grid.grow(maximumRowIndex + 1);
-        for (size_t row = oldRowSize; row < gridRowCount(); ++row)
-            m_grid[row].grow(gridColumnCount());
-    }
-
-    if (maximumColumnIndex >= gridColumnCount()) {
-        for (size_t row = 0; row < gridRowCount(); ++row)
-            m_grid[row].grow(maximumColumnIndex + 1);
-    }
-}
-
-void RenderGrid::insertItemIntoGrid(LayoutBox& child, const GridCoordinate& coordinate)
-{
-    ensureGridSize(coordinate.rows.resolvedFinalPosition.toInt(), coordinate.columns.resolvedFinalPosition.toInt());
-
-    for (GridSpan::iterator row = coordinate.rows.begin(); row != coordinate.rows.end(); ++row) {
-        for (GridSpan::iterator column = coordinate.columns.begin(); column != coordinate.columns.end(); ++column)
-            m_grid[row.toInt()][column.toInt()].append(&child);
-    }
-
-    RELEASE_ASSERT(!m_gridItemCoordinate.contains(&child));
-    m_gridItemCoordinate.set(&child, coordinate);
-}
-
-void RenderGrid::placeItemsOnGrid()
-{
-    if (!gridIsDirty())
-        return;
-
-    ASSERT(m_gridItemCoordinate.isEmpty());
-
-    populateExplicitGridAndOrderIterator();
-
-    // We clear the dirty bit here as the grid sizes have been updated, this means
-    // that we can safely call gridRowCount() / gridColumnCount().
-    m_gridIsDirty = false;
-
-    Vector<LayoutBox*> autoMajorAxisAutoGridItems;
-    Vector<LayoutBox*> specifiedMajorAxisAutoGridItems;
-    for (LayoutBox* child = m_orderIterator.first(); child; child = m_orderIterator.next()) {
-        if (child->isOutOfFlowPositioned())
-            continue;
-
-        OwnPtr<GridSpan> rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForRows);
-        OwnPtr<GridSpan> columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForColumns);
-        if (!rowPositions || !columnPositions) {
-            GridSpan* majorAxisPositions = (autoPlacementMajorAxisDirection() == ForColumns) ? columnPositions.get() : rowPositions.get();
-            if (!majorAxisPositions)
-                autoMajorAxisAutoGridItems.append(child);
-            else
-                specifiedMajorAxisAutoGridItems.append(child);
-            continue;
-        }
-        insertItemIntoGrid(*child, GridCoordinate(*rowPositions, *columnPositions));
-    }
-
-    ASSERT(gridRowCount() >= GridResolvedPosition::explicitGridRowCount(*style()));
-    ASSERT(gridColumnCount() >= GridResolvedPosition::explicitGridColumnCount(*style()));
-
-    placeSpecifiedMajorAxisItemsOnGrid(specifiedMajorAxisAutoGridItems);
-    placeAutoMajorAxisItemsOnGrid(autoMajorAxisAutoGridItems);
-
-    m_grid.shrinkToFit();
-}
-
-void RenderGrid::populateExplicitGridAndOrderIterator()
-{
-    OrderIteratorPopulator populator(m_orderIterator);
-
-    size_t maximumRowIndex = std::max<size_t>(1, GridResolvedPosition::explicitGridRowCount(*style()));
-    size_t maximumColumnIndex = std::max<size_t>(1, GridResolvedPosition::explicitGridColumnCount(*style()));
-
-    ASSERT(m_gridItemsIndexesMap.isEmpty());
-    size_t childIndex = 0;
-    for (LayoutBox* child = firstChildBox(); child; child = child->nextInFlowSiblingBox()) {
-        populator.collectChild(child);
-        m_gridItemsIndexesMap.set(child, childIndex++);
-
-        // This function bypasses the cache (cachedGridCoordinate()) as it is used to build it.
-        OwnPtr<GridSpan> rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForRows);
-        OwnPtr<GridSpan> columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForColumns);
-
-        // |positions| is 0 if we need to run the auto-placement algorithm.
-        if (rowPositions) {
-            maximumRowIndex = std::max<size_t>(maximumRowIndex, rowPositions->resolvedFinalPosition.next().toInt());
-        } else {
-            // Grow the grid for items with a definite row span, getting the largest such span.
-            GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *child, ForRows, GridResolvedPosition(0));
-            maximumRowIndex = std::max<size_t>(maximumRowIndex, positions.resolvedFinalPosition.next().toInt());
-        }
-
-        if (columnPositions) {
-            maximumColumnIndex = std::max<size_t>(maximumColumnIndex, columnPositions->resolvedFinalPosition.next().toInt());
-        } else {
-            // Grow the grid for items with a definite column span, getting the largest such span.
-            GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *child, ForColumns, GridResolvedPosition(0));
-            maximumColumnIndex = std::max<size_t>(maximumColumnIndex, positions.resolvedFinalPosition.next().toInt());
-        }
-    }
-
-    m_grid.grow(maximumRowIndex);
-    for (auto& column : m_grid)
-        column.grow(maximumColumnIndex);
-}
-
-PassOwnPtr<GridCoordinate> RenderGrid::createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(const LayoutBox& gridItem, GridTrackSizingDirection specifiedDirection, const GridSpan& specifiedPositions) const
-{
-    GridTrackSizingDirection crossDirection = specifiedDirection == ForColumns ? ForRows : ForColumns;
-    const size_t endOfCrossDirection = crossDirection == ForColumns ? gridColumnCount() : gridRowCount();
-    GridSpan crossDirectionPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), gridItem, crossDirection, GridResolvedPosition(endOfCrossDirection));
-    return adoptPtr(new GridCoordinate(specifiedDirection == ForColumns ? crossDirectionPositions : specifiedPositions, specifiedDirection == ForColumns ? specifiedPositions : crossDirectionPositions));
-}
-
-void RenderGrid::placeSpecifiedMajorAxisItemsOnGrid(const Vector<LayoutBox*>& autoGridItems)
-{
-    bool isForColumns = autoPlacementMajorAxisDirection() == ForColumns;
-    bool isGridAutoFlowDense = style()->isGridAutoFlowAlgorithmDense();
-
-    // Mapping between the major axis tracks (rows or columns) and the last auto-placed item's position inserted on
-    // that track. This is needed to implement "sparse" packing for items locked to a given track.
-    // See http://dev.w3.org/csswg/css-grid/#auto-placement-algo
-    HashMap<unsigned, unsigned, DefaultHash<unsigned>::Hash, WTF::UnsignedWithZeroKeyHashTraits<unsigned>> minorAxisCursors;
-
-    for (const auto& autoGridItem : autoGridItems) {
-        OwnPtr<GridSpan> majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *autoGridItem, autoPlacementMajorAxisDirection());
-        GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *autoGridItem, autoPlacementMinorAxisDirection(), GridResolvedPosition(0));
-        unsigned majorAxisInitialPosition = majorAxisPositions->resolvedInitialPosition.toInt();
-
-        GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions->resolvedInitialPosition.toInt(), isGridAutoFlowDense ? 0 : minorAxisCursors.get(majorAxisInitialPosition));
-        OwnPtr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions->integerSpan(), minorAxisPositions.integerSpan());
-        if (!emptyGridArea)
-            emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(*autoGridItem, autoPlacementMajorAxisDirection(), *majorAxisPositions);
-        insertItemIntoGrid(*autoGridItem, *emptyGridArea);
-
-        if (!isGridAutoFlowDense)
-            minorAxisCursors.set(majorAxisInitialPosition, isForColumns ? emptyGridArea->rows.resolvedInitialPosition.toInt() : emptyGridArea->columns.resolvedInitialPosition.toInt());
-    }
-}
-
-void RenderGrid::placeAutoMajorAxisItemsOnGrid(const Vector<LayoutBox*>& autoGridItems)
-{
-    std::pair<size_t, size_t> autoPlacementCursor = std::make_pair(0, 0);
-    bool isGridAutoFlowDense = style()->isGridAutoFlowAlgorithmDense();
-
-    for (const auto& autoGridItem : autoGridItems) {
-        placeAutoMajorAxisItemOnGrid(*autoGridItem, autoPlacementCursor);
-
-        // If grid-auto-flow is dense, reset auto-placement cursor.
-        if (isGridAutoFlowDense) {
-            autoPlacementCursor.first = 0;
-            autoPlacementCursor.second = 0;
-        }
-    }
-}
-
-void RenderGrid::placeAutoMajorAxisItemOnGrid(LayoutBox& gridItem, std::pair<size_t, size_t>& autoPlacementCursor)
-{
-    OwnPtr<GridSpan> minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), gridItem, autoPlacementMinorAxisDirection());
-    ASSERT(!GridResolvedPosition::resolveGridPositionsFromStyle(*style(), gridItem, autoPlacementMajorAxisDirection()));
-    GridSpan majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), gridItem, autoPlacementMajorAxisDirection(), GridResolvedPosition(0));
-
-    const size_t endOfMajorAxis = (autoPlacementMajorAxisDirection() == ForColumns) ? gridColumnCount() : gridRowCount();
-    size_t majorAxisAutoPlacementCursor = autoPlacementMajorAxisDirection() == ForColumns ? autoPlacementCursor.second : autoPlacementCursor.first;
-    size_t minorAxisAutoPlacementCursor = autoPlacementMajorAxisDirection() == ForColumns ? autoPlacementCursor.first : autoPlacementCursor.second;
-
-    OwnPtr<GridCoordinate> emptyGridArea;
-    if (minorAxisPositions) {
-        // Move to the next track in major axis if initial position in minor axis is before auto-placement cursor.
-        if (minorAxisPositions->resolvedInitialPosition.toInt() < minorAxisAutoPlacementCursor)
-            majorAxisAutoPlacementCursor++;
-
-        if (majorAxisAutoPlacementCursor < endOfMajorAxis) {
-            GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisPositions->resolvedInitialPosition.toInt(), majorAxisAutoPlacementCursor);
-            emptyGridArea = iterator.nextEmptyGridArea(minorAxisPositions->integerSpan(), majorAxisPositions.integerSpan());
-        }
-
-        if (!emptyGridArea)
-            emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(gridItem, autoPlacementMinorAxisDirection(), *minorAxisPositions);
-    } else {
-        GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), gridItem, autoPlacementMinorAxisDirection(), GridResolvedPosition(0));
-
-        for (size_t majorAxisIndex = majorAxisAutoPlacementCursor; majorAxisIndex < endOfMajorAxis; ++majorAxisIndex) {
-            GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisIndex, minorAxisAutoPlacementCursor);
-            emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions.integerSpan(), minorAxisPositions.integerSpan());
-
-            if (emptyGridArea) {
-                // Check that it fits in the minor axis direction, as we shouldn't grow in that direction here (it was already managed in populateExplicitGridAndOrderIterator()).
-                GridResolvedPosition minorAxisFinalPositionIndex = autoPlacementMinorAxisDirection() == ForColumns ? emptyGridArea->columns.resolvedFinalPosition : emptyGridArea->rows.resolvedFinalPosition;
-                const size_t endOfMinorAxis = autoPlacementMinorAxisDirection() == ForColumns ? gridColumnCount() : gridRowCount();
-                if (minorAxisFinalPositionIndex.toInt() < endOfMinorAxis)
-                    break;
-
-                // Discard empty grid area as it does not fit in the minor axis direction.
-                // We don't need to create a new empty grid area yet as we might find a valid one in the next iteration.
-                emptyGridArea = nullptr;
-            }
-
-            // As we're moving to the next track in the major axis we should reset the auto-placement cursor in the minor axis.
-            minorAxisAutoPlacementCursor = 0;
-        }
-
-        if (!emptyGridArea)
-            emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(gridItem, autoPlacementMinorAxisDirection(), minorAxisPositions);
-    }
-
-    insertItemIntoGrid(gridItem, *emptyGridArea);
-    // Move auto-placement cursor to the new position.
-    autoPlacementCursor.first = emptyGridArea->rows.resolvedInitialPosition.toInt();
-    autoPlacementCursor.second = emptyGridArea->columns.resolvedInitialPosition.toInt();
-}
-
-GridTrackSizingDirection RenderGrid::autoPlacementMajorAxisDirection() const
-{
-    return style()->isGridAutoFlowDirectionColumn() ? ForColumns : ForRows;
-}
-
-GridTrackSizingDirection RenderGrid::autoPlacementMinorAxisDirection() const
-{
-    return style()->isGridAutoFlowDirectionColumn() ? ForRows : ForColumns;
-}
-
-void RenderGrid::dirtyGrid()
-{
-    // Even if this could be redundant, it could be seen as a defensive strategy against
-    // style changes events happening during the layout phase or even while the painting process
-    // is still ongoing.
-    // Forcing a new layout for the Grid render would cancel any ongoing painting and ensure
-    // the grid and its children are correctly laid out according to the new style rules.
-    setNeedsLayout();
-
-    m_grid.resize(0);
-    m_gridItemCoordinate.clear();
-    m_gridIsDirty = true;
-    m_gridItemsOverflowingGridArea.resize(0);
-    m_gridItemsIndexesMap.clear();
-}
-
-void RenderGrid::layoutGridItems()
-{
-    placeItemsOnGrid();
-
-    LayoutUnit availableSpaceForColumns = availableLogicalWidth();
-    LayoutUnit availableSpaceForRows = availableLogicalHeight(IncludeMarginBorderPadding);
-    GridSizingData sizingData(gridColumnCount(), gridRowCount());
-    computeUsedBreadthOfGridTracks(ForColumns, sizingData, availableSpaceForColumns);
-    ASSERT(tracksAreWiderThanMinTrackBreadth(ForColumns, sizingData.columnTracks));
-    computeUsedBreadthOfGridTracks(ForRows, sizingData, availableSpaceForRows);
-    ASSERT(tracksAreWiderThanMinTrackBreadth(ForRows, sizingData.rowTracks));
-
-    populateGridPositions(sizingData, availableSpaceForColumns, availableSpaceForRows);
-    m_gridItemsOverflowingGridArea.resize(0);
-
-    LayoutUnit columnOffset = contentPositionAndDistributionColumnOffset(availableSpaceForColumns, style()->justifyContent(), style()->justifyContentDistribution(), style()->justifyContentOverflowAlignment(), m_columnPositions.size() - 1);
-    LayoutUnit rowOffset = contentPositionAndDistributionRowOffset(availableSpaceForRows, style()->alignContent(), style()->alignContentDistribution(), style()->alignContentOverflowAlignment(), m_rowPositions.size() - 1);
-    LayoutSize contentPositionOffset(columnOffset, rowOffset);
-
-    for (LayoutBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
-        if (child->isOutOfFlowPositioned()) {
-            child->containingBlock()->insertPositionedObject(child);
-            continue;
-        }
-
-        // Because the grid area cannot be styled, we don't need to adjust
-        // the grid breadth to account for 'box-sizing'.
-        LayoutUnit oldOverrideContainingBlockContentLogicalWidth = child->hasOverrideContainingBlockLogicalWidth() ? child->overrideContainingBlockContentLogicalWidth() : LayoutUnit();
-        LayoutUnit oldOverrideContainingBlockContentLogicalHeight = child->hasOverrideContainingBlockLogicalHeight() ? child->overrideContainingBlockContentLogicalHeight() : LayoutUnit();
-
-        LayoutUnit overrideContainingBlockContentLogicalWidth = gridAreaBreadthForChild(*child, ForColumns, sizingData.columnTracks);
-        LayoutUnit overrideContainingBlockContentLogicalHeight = gridAreaBreadthForChild(*child, ForRows, sizingData.rowTracks);
-
-        SubtreeLayoutScope layoutScope(*child);
-        if (oldOverrideContainingBlockContentLogicalWidth != overrideContainingBlockContentLogicalWidth || (oldOverrideContainingBlockContentLogicalHeight != overrideContainingBlockContentLogicalHeight && child->hasRelativeLogicalHeight()))
-            layoutScope.setNeedsLayout(child);
-
-        child->setOverrideContainingBlockContentLogicalWidth(overrideContainingBlockContentLogicalWidth);
-        child->setOverrideContainingBlockContentLogicalHeight(overrideContainingBlockContentLogicalHeight);
-
-        // Stretching logic might force a child layout, so we need to run it before the layoutIfNeeded
-        // call to avoid unnecessary relayouts. This might imply that child margins, needed to correctly
-        // determine the available space before stretching, are not set yet.
-        applyStretchAlignmentToChildIfNeeded(*child, overrideContainingBlockContentLogicalHeight);
-
-        child->layoutIfNeeded();
-
-#if ENABLE(ASSERT)
-        const GridCoordinate& coordinate = cachedGridCoordinate(*child);
-        ASSERT(coordinate.columns.resolvedInitialPosition.toInt() < sizingData.columnTracks.size());
-        ASSERT(coordinate.rows.resolvedInitialPosition.toInt() < sizingData.rowTracks.size());
-#endif
-        child->setLogicalLocation(findChildLogicalPosition(*child, contentPositionOffset));
-
-        // Keep track of children overflowing their grid area as we might need to paint them even if the grid-area is
-        // not visible
-        if (child->logicalHeight() > overrideContainingBlockContentLogicalHeight
-            || child->logicalWidth() > overrideContainingBlockContentLogicalWidth)
-            m_gridItemsOverflowingGridArea.append(child);
-    }
-
-    for (const auto& row : sizingData.rowTracks)
-        setLogicalHeight(logicalHeight() + row.baseSize());
-
-    // Min / max logical height is handled by the call to updateLogicalHeight in layoutBlock.
-
-    setLogicalHeight(logicalHeight() + borderAndPaddingLogicalHeight());
-}
-
-void RenderGrid::layoutPositionedObjects(bool relayoutChildren, PositionedLayoutBehavior info)
-{
-    TrackedRendererListHashSet* positionedDescendants = positionedObjects();
-    if (!positionedDescendants)
-        return;
-
-    bool containerHasHorizontalWritingMode = isHorizontalWritingMode();
-    for (auto* child : *positionedDescendants) {
-        bool hasOrthogonalWritingMode = child->isHorizontalWritingMode() != containerHasHorizontalWritingMode;
-        if (hasOrthogonalWritingMode) {
-            // FIXME: Properly support orthogonal writing mode.
-            continue;
-        }
-
-        // FIXME: Detect properly if start/end is auto for inexistent named grid lines.
-        bool columnStartIsAuto = child->style()->gridColumnStart().isAuto();
-        LayoutUnit columnOffset = LayoutUnit(0);
-        LayoutUnit columnBreadth = LayoutUnit(0);
-        offsetAndBreadthForPositionedChild(*child, ForColumns, columnStartIsAuto, child->style()->gridColumnEnd().isAuto(), columnOffset, columnBreadth);
-        bool rowStartIsAuto = child->style()->gridRowStart().isAuto();
-        LayoutUnit rowOffset = LayoutUnit(0);
-        LayoutUnit rowBreadth = LayoutUnit(0);
-        offsetAndBreadthForPositionedChild(*child, ForRows, rowStartIsAuto, child->style()->gridRowEnd().isAuto(), rowOffset, rowBreadth);
-
-        child->setOverrideContainingBlockContentLogicalWidth(columnBreadth);
-        child->setOverrideContainingBlockContentLogicalHeight(rowBreadth);
-        child->setExtraInlineOffset(columnOffset);
-        child->setExtraBlockOffset(rowOffset);
-
-        if (child->parent() == this) {
-            // If column/row start is not auto the padding has been already computed in offsetAndBreadthForPositionedChild().
-            Layer* childLayer = child->layer();
-            if (columnStartIsAuto)
-                childLayer->setStaticInlinePosition(borderAndPaddingStart());
-            else
-                childLayer->setStaticInlinePosition(borderStart() + columnOffset);
-            if (rowStartIsAuto)
-                childLayer->setStaticBlockPosition(borderAndPaddingBefore());
-            else
-                childLayer->setStaticBlockPosition(borderBefore() + rowOffset);
-        }
-    }
-
-    RenderBlock::layoutPositionedObjects(relayoutChildren, info);
-}
-
-void RenderGrid::offsetAndBreadthForPositionedChild(const LayoutBox& child, GridTrackSizingDirection direction, bool startIsAuto, bool endIsAuto, LayoutUnit& offset, LayoutUnit& breadth)
-{
-    ASSERT(child.isHorizontalWritingMode() == isHorizontalWritingMode());
-
-    OwnPtr<GridSpan> positions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), child, direction);
-    if (!positions) {
-        offset = LayoutUnit(0);
-        breadth = (direction == ForColumns) ? clientLogicalWidth() : clientLogicalHeight();
-        return;
-    }
-
-    GridResolvedPosition firstPosition = GridResolvedPosition(0);
-    GridResolvedPosition initialPosition = startIsAuto ? firstPosition : positions->resolvedInitialPosition;
-    GridResolvedPosition lastPosition = GridResolvedPosition((direction == ForColumns ? gridColumnCount() : gridRowCount()) - 1);
-    GridResolvedPosition finalPosition = endIsAuto ? lastPosition : positions->resolvedFinalPosition;
-
-    // Positioned children do not grow the grid, so we need to clamp the positions to avoid ending up outside of it.
-    initialPosition = std::min<GridResolvedPosition>(initialPosition, lastPosition);
-    finalPosition = std::min<GridResolvedPosition>(finalPosition, lastPosition);
-
-    LayoutUnit start = startIsAuto ? LayoutUnit(0) : (direction == ForColumns) ?  m_columnPositions[initialPosition.toInt()] : m_rowPositions[initialPosition.toInt()];
-    LayoutUnit end = endIsAuto ? (direction == ForColumns) ? logicalWidth() : logicalHeight() : (direction == ForColumns) ?  m_columnPositions[finalPosition.next().toInt()] : m_rowPositions[finalPosition.next().toInt()];
-
-    breadth = end - start;
-
-    if (startIsAuto)
-        breadth -= (direction == ForColumns) ? borderStart() : borderBefore();
-    else
-        start -= ((direction == ForColumns) ? borderStart() : borderBefore());
-
-    if (endIsAuto) {
-        breadth -= (direction == ForColumns) ? borderEnd() : borderAfter();
-        breadth -= scrollbarLogicalWidth();
-    }
-
-    offset = start;
-}
-
-GridCoordinate RenderGrid::cachedGridCoordinate(const LayoutBox& gridItem) const
-{
-    ASSERT(m_gridItemCoordinate.contains(&gridItem));
-    return m_gridItemCoordinate.get(&gridItem);
-}
-
-LayoutUnit RenderGrid::gridAreaBreadthForChild(const LayoutBox& child, GridTrackSizingDirection direction, const Vector<GridTrack>& tracks) const
-{
-    const GridCoordinate& coordinate = cachedGridCoordinate(child);
-    const GridSpan& span = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
-    LayoutUnit gridAreaBreadth = 0;
-    for (GridSpan::iterator trackPosition = span.begin(); trackPosition != span.end(); ++trackPosition)
-        gridAreaBreadth += tracks[trackPosition.toInt()].baseSize();
-    return gridAreaBreadth;
-}
-
-void RenderGrid::populateGridPositions(const GridSizingData& sizingData, LayoutUnit availableSpaceForColumns, LayoutUnit availableSpaceForRows)
-{
-    unsigned numberOfColumnTracks = sizingData.columnTracks.size();
-    unsigned numberOfRowTracks = sizingData.rowTracks.size();
-
-    m_columnPositions.resize(numberOfColumnTracks + 1);
-    m_columnPositions[0] = borderAndPaddingStart();
-    for (unsigned i = 0; i < numberOfColumnTracks; ++i)
-        m_columnPositions[i + 1] = m_columnPositions[i] + sizingData.columnTracks[i].baseSize();
-
-    m_rowPositions.resize(numberOfRowTracks + 1);
-    m_rowPositions[0] = borderAndPaddingBefore();
-    for (unsigned i = 0; i < numberOfRowTracks; ++i)
-        m_rowPositions[i + 1] = m_rowPositions[i] + sizingData.rowTracks[i].baseSize();
-}
-
-static LayoutUnit computeOverflowAlignmentOffset(OverflowAlignment overflow, LayoutUnit startOfTrack, LayoutUnit endOfTrack, LayoutUnit childBreadth)
-{
-    LayoutUnit trackBreadth = endOfTrack - startOfTrack;
-    LayoutUnit offset = trackBreadth - childBreadth;
-
-    // If overflow is 'safe', we have to make sure we don't overflow the 'start'
-    // edge (potentially cause some data loss as the overflow is unreachable).
-    if (overflow == OverflowAlignmentSafe)
-        offset = std::max<LayoutUnit>(0, offset);
-
-    // If we overflow our alignment container and overflow is 'true' (default), we
-    // ignore the overflow and just return the value regardless (which may cause data
-    // loss as we overflow the 'start' edge).
-    return offset;
-}
-
-LayoutUnit RenderGrid::startOfColumnForChild(const LayoutBox& child) const
-{
-    const GridCoordinate& coordinate = cachedGridCoordinate(child);
-    LayoutUnit startOfColumn = m_columnPositions[coordinate.columns.resolvedInitialPosition.toInt()];
-    // The grid items should be inside the grid container's border box, that's why they need to be shifted.
-    return startOfColumn + marginStartForChild(child);
-}
-
-LayoutUnit RenderGrid::endOfColumnForChild(const LayoutBox& child) const
-{
-    const GridCoordinate& coordinate = cachedGridCoordinate(child);
-    LayoutUnit startOfColumn = m_columnPositions[coordinate.columns.resolvedInitialPosition.toInt()];
-    // The grid items should be inside the grid container's border box, that's why they need to be shifted.
-    LayoutUnit columnPosition = startOfColumn + marginStartForChild(child);
-
-    LayoutUnit endOfColumn = m_columnPositions[coordinate.columns.resolvedFinalPosition.next().toInt()];
-    // FIXME: This might not work as expected with orthogonal writing-modes.
-    LayoutUnit offsetFromColumnPosition = computeOverflowAlignmentOffset(child.style()->justifySelfOverflowAlignment(), startOfColumn, endOfColumn, child.logicalWidth() + child.marginLogicalWidth());
-
-    return columnPosition + offsetFromColumnPosition;
-}
-
-LayoutUnit RenderGrid::columnPositionLeft(const LayoutBox& child) const
-{
-    if (style()->isLeftToRightDirection())
-        return startOfColumnForChild(child);
-
-    return endOfColumnForChild(child);
-}
-
-LayoutUnit RenderGrid::columnPositionRight(const LayoutBox& child) const
-{
-    if (!style()->isLeftToRightDirection())
-        return startOfColumnForChild(child);
-
-    return endOfColumnForChild(child);
-}
-
-LayoutUnit RenderGrid::centeredColumnPositionForChild(const LayoutBox& child) const
-{
-    const GridCoordinate& coordinate = cachedGridCoordinate(child);
-    LayoutUnit startOfColumn = m_columnPositions[coordinate.columns.resolvedInitialPosition.toInt()];
-    LayoutUnit endOfColumn = m_columnPositions[coordinate.columns.resolvedFinalPosition.next().toInt()];
-    LayoutUnit columnPosition = startOfColumn + marginStartForChild(child);
-    // FIXME: This might not work as expected with orthogonal writing-modes.
-    LayoutUnit offsetFromColumnPosition = computeOverflowAlignmentOffset(child.style()->justifySelfOverflowAlignment(), startOfColumn, endOfColumn, child.logicalWidth() + child.marginLogicalWidth());
-
-    return columnPosition + offsetFromColumnPosition / 2;
-}
-
-LayoutUnit RenderGrid::columnPositionForChild(const LayoutBox& child) const
-{
-    bool hasOrthogonalWritingMode = child.isHorizontalWritingMode() != isHorizontalWritingMode();
-
-    switch (LayoutStyle::resolveJustification(styleRef(), child.styleRef(), ItemPositionStretch)) {
-    case ItemPositionSelfStart:
-        // For orthogonal writing-modes, this computes to 'start'
-        // FIXME: grid track sizing and positioning do not support orthogonal modes yet.
-        if (hasOrthogonalWritingMode)
-            return startOfColumnForChild(child);
-
-        // self-start is based on the child's direction. That's why we need to check against the grid container's direction.
-        if (child.style()->direction() != style()->direction())
-            return endOfColumnForChild(child);
-
-        return startOfColumnForChild(child);
-    case ItemPositionSelfEnd:
-        // For orthogonal writing-modes, this computes to 'start'
-        // FIXME: grid track sizing and positioning do not support orthogonal modes yet.
-        if (hasOrthogonalWritingMode)
-            return endOfColumnForChild(child);
-
-        // self-end is based on the child's direction. That's why we need to check against the grid container's direction.
-        if (child.style()->direction() != style()->direction())
-            return startOfColumnForChild(child);
-
-        return endOfColumnForChild(child);
-    case ItemPositionFlexStart:
-        // Only used in flex layout, for other layout, it's equivalent to 'start'.
-        return startOfColumnForChild(child);
-    case ItemPositionFlexEnd:
-        // Only used in flex layout, for other layout, it's equivalent to 'end'.
-        return endOfColumnForChild(child);
-    case ItemPositionLeft:
-        return columnPositionLeft(child);
-    case ItemPositionRight:
-        return columnPositionRight(child);
-    case ItemPositionCenter:
-        return centeredColumnPositionForChild(child);
-    case ItemPositionStart:
-        return startOfColumnForChild(child);
-    case ItemPositionEnd:
-        return endOfColumnForChild(child);
-    case ItemPositionAuto:
-        break;
-    case ItemPositionStretch:
-        return startOfColumnForChild(child);
-    case ItemPositionBaseline:
-    case ItemPositionLastBaseline:
-        // FIXME: Implement the previous values. For now, we always 'start' align the child.
-        return startOfColumnForChild(child);
-    }
-
-    ASSERT_NOT_REACHED();
-    return 0;
-}
-
-LayoutUnit RenderGrid::endOfRowForChild(const LayoutBox& child) const
-{
-    const GridCoordinate& coordinate = cachedGridCoordinate(child);
-
-    LayoutUnit startOfRow = m_rowPositions[coordinate.rows.resolvedInitialPosition.toInt()];
-    // The grid items should be inside the grid container's border box, that's why they need to be shifted.
-    LayoutUnit rowPosition = startOfRow + marginBeforeForChild(child);
-
-    LayoutUnit endOfRow = m_rowPositions[coordinate.rows.resolvedFinalPosition.next().toInt()];
-    LayoutUnit offsetFromRowPosition = computeOverflowAlignmentOffset(child.style()->alignSelfOverflowAlignment(), startOfRow, endOfRow, child.logicalHeight() + child.marginLogicalHeight());
-
-    return rowPosition + offsetFromRowPosition;
-}
-
-LayoutUnit RenderGrid::startOfRowForChild(const LayoutBox& child) const
-{
-    const GridCoordinate& coordinate = cachedGridCoordinate(child);
-
-    LayoutUnit startOfRow = m_rowPositions[coordinate.rows.resolvedInitialPosition.toInt()];
-    // The grid items should be inside the grid container's border box, that's why they need to be shifted.
-    LayoutUnit rowPosition = startOfRow + marginBeforeForChild(child);
-
-    return rowPosition;
-}
-
-LayoutUnit RenderGrid::centeredRowPositionForChild(const LayoutBox& child) const
-{
-    const GridCoordinate& coordinate = cachedGridCoordinate(child);
-
-    // The grid items should be inside the grid container's border box, that's why they need to be shifted.
-    LayoutUnit startOfRow = m_rowPositions[coordinate.rows.resolvedInitialPosition.toInt()];
-    LayoutUnit endOfRow = m_rowPositions[coordinate.rows.resolvedFinalPosition.next().toInt()];
-    LayoutUnit rowPosition = startOfRow + marginBeforeForChild(child);
-    LayoutUnit offsetFromRowPosition = computeOverflowAlignmentOffset(child.style()->alignSelfOverflowAlignment(), startOfRow, endOfRow, child.logicalHeight() + child.marginLogicalHeight());
-
-    return rowPosition + offsetFromRowPosition / 2;
-}
-
-static inline LayoutUnit constrainedChildIntrinsicContentLogicalHeight(const LayoutBox& child)
-{
-    LayoutUnit childIntrinsicContentLogicalHeight = child.intrinsicContentLogicalHeight();
-    return child.constrainLogicalHeightByMinMax(childIntrinsicContentLogicalHeight + child.borderAndPaddingLogicalHeight(), childIntrinsicContentLogicalHeight);
-}
-
-bool RenderGrid::allowedToStretchLogicalHeightForChild(const LayoutBox& child) const
-{
-    return child.style()->logicalHeight().isAuto() && !child.style()->marginBeforeUsing(style()).isAuto() && !child.style()->marginAfterUsing(style()).isAuto();
-}
-
-// FIXME: This logic is shared by RenderFlexibleBox, so it should be moved to LayoutBox.
-bool RenderGrid::needToStretchChildLogicalHeight(const LayoutBox& child) const
-{
-    if (LayoutStyle::resolveAlignment(styleRef(), child.styleRef(), ItemPositionStretch) != ItemPositionStretch)
-        return false;
-
-    return isHorizontalWritingMode() && child.style()->height().isAuto();
-}
-
-// FIXME: This logic is shared by RenderFlexibleBox, so it should be moved to LayoutBox.
-LayoutUnit RenderGrid::childIntrinsicHeight(const LayoutBox& child) const
-{
-    if (child.isHorizontalWritingMode() && needToStretchChildLogicalHeight(child))
-        return constrainedChildIntrinsicContentLogicalHeight(child);
-    return child.size().height();
-}
-
-// FIXME: This logic is shared by RenderFlexibleBox, so it should be moved to LayoutBox.
-LayoutUnit RenderGrid::childIntrinsicWidth(const LayoutBox& child) const
-{
-    if (!child.isHorizontalWritingMode() && needToStretchChildLogicalHeight(child))
-        return constrainedChildIntrinsicContentLogicalHeight(child);
-    return child.size().width();
-}
-
-// FIXME: This logic is shared by RenderFlexibleBox, so it should be moved to LayoutBox.
-LayoutUnit RenderGrid::intrinsicLogicalHeightForChild(const LayoutBox& child) const
-{
-    return isHorizontalWritingMode() ? childIntrinsicHeight(child) : childIntrinsicWidth(child);
-}
-
-// FIXME: This logic is shared by RenderFlexibleBox, so it should be moved to LayoutBox.
-LayoutUnit RenderGrid::marginLogicalHeightForChild(const LayoutBox& child) const
-{
-    return isHorizontalWritingMode() ? child.marginHeight() : child.marginWidth();
-}
-
-LayoutUnit RenderGrid::computeMarginLogicalHeightForChild(const LayoutBox& child) const
-{
-    LayoutUnit marginBefore;
-    LayoutUnit marginAfter;
-    child.computeMarginsForDirection(BlockDirection, this, child.containingBlockLogicalWidthForContent(), child.logicalHeight(), marginBefore, marginAfter,
-        child.style()->marginBeforeUsing(style()),
-        child.style()->marginAfterUsing(style()));
-
-    return marginBefore + marginAfter;
-}
-
-LayoutUnit RenderGrid::availableAlignmentSpaceForChildBeforeStretching(LayoutUnit gridAreaBreadthForChild, const LayoutBox& child) const
-{
-    LayoutUnit childMarginLogicalHeight = marginLogicalHeightForChild(child);
-
-    // Because we want to avoid multiple layouts, stretching logic might be performed before
-    // children are laid out, so we can't use the child cached values. Hence, we need to
-    // compute margins in order to determine the available height before stretching.
-    if (childMarginLogicalHeight == 0)
-        childMarginLogicalHeight = computeMarginLogicalHeightForChild(child);
-
-    LayoutUnit childLogicalHeight = childMarginLogicalHeight + intrinsicLogicalHeightForChild(child);
-    return gridAreaBreadthForChild - childLogicalHeight;
-}
-
-// FIXME: This logic is shared by RenderFlexibleBox, so it should be moved to LayoutBox.
-void RenderGrid::applyStretchAlignmentToChildIfNeeded(LayoutBox& child, LayoutUnit gridAreaBreadthForChild)
-{
-    if (LayoutStyle::resolveAlignment(styleRef(), child.styleRef(), ItemPositionStretch) != ItemPositionStretch)
-        return;
-
-    bool hasOrthogonalWritingMode = child.isHorizontalWritingMode() != isHorizontalWritingMode();
-    if (allowedToStretchLogicalHeightForChild(child)) {
-        // FIXME: If the child has orthogonal flow, then it already has an override height set, so use it.
-        // FIXME: grid track sizing and positioning do not support orthogonal modes yet.
-        if (!hasOrthogonalWritingMode) {
-            LayoutUnit heightBeforeStretching = needToStretchChildLogicalHeight(child) ? constrainedChildIntrinsicContentLogicalHeight(child) : child.logicalHeight();
-            LayoutUnit stretchedLogicalHeight = heightBeforeStretching + availableAlignmentSpaceForChildBeforeStretching(gridAreaBreadthForChild, child);
-            LayoutUnit desiredLogicalHeight = child.constrainLogicalHeightByMinMax(stretchedLogicalHeight, heightBeforeStretching - child.borderAndPaddingLogicalHeight());
-            LayoutUnit desiredLogicalContentHeight = desiredLogicalHeight - child.borderAndPaddingLogicalHeight();
-
-            // FIXME: Can avoid laying out here in some cases. See https://webkit.org/b/87905.
-            if (desiredLogicalHeight != child.logicalHeight() || !child.hasOverrideHeight() || desiredLogicalContentHeight != child.overrideLogicalContentHeight()) {
-                child.setOverrideLogicalContentHeight(desiredLogicalContentHeight);
-                child.setLogicalHeight(0);
-                child.forceChildLayout();
-            }
-        }
-    }
-}
-
-LayoutUnit RenderGrid::rowPositionForChild(const LayoutBox& child) const
-{
-    bool hasOrthogonalWritingMode = child.isHorizontalWritingMode() != isHorizontalWritingMode();
-    switch (LayoutStyle::resolveAlignment(styleRef(), child.styleRef(), ItemPositionStretch)) {
-    case ItemPositionSelfStart:
-        // If orthogonal writing-modes, this computes to 'start'.
-        // FIXME: grid track sizing and positioning do not support orthogonal modes yet.
-        if (hasOrthogonalWritingMode)
-            return startOfRowForChild(child);
-
-        // self-start is based on the child's block axis direction. That's why we need to check against the grid container's block flow.
-        if (child.style()->writingMode() != style()->writingMode())
-            return endOfRowForChild(child);
-
-        return startOfRowForChild(child);
-    case ItemPositionSelfEnd:
-        // If orthogonal writing-modes, this computes to 'end'.
-        // FIXME: grid track sizing and positioning do not support orthogonal modes yet.
-        if (hasOrthogonalWritingMode)
-            return endOfRowForChild(child);
-
-        // self-end is based on the child's block axis direction. That's why we need to check against the grid container's block flow.
-        if (child.style()->writingMode() != style()->writingMode())
-            return startOfRowForChild(child);
-
-        return endOfRowForChild(child);
-    case ItemPositionLeft:
-        // The alignment axis (column axis) and the inline axis are parallell in
-        // orthogonal writing mode.
-        // FIXME: grid track sizing and positioning do not support orthogonal modes yet.
-        if (hasOrthogonalWritingMode)
-            return startOfRowForChild(child);
-
-        // Otherwise this this is equivalent to 'start'.
-        return startOfRowForChild(child);
-    case ItemPositionRight:
-        // The alignment axis (column axis) and the inline axis are parallell in
-        // orthogonal writing mode.
-        // FIXME: grid track sizing and positioning do not support orthogonal modes yet.
-        if (hasOrthogonalWritingMode)
-            return endOfRowForChild(child);
-
-        // Otherwise this this is equivalent to 'start'.
-        return startOfRowForChild(child);
-    case ItemPositionCenter:
-        return centeredRowPositionForChild(child);
-        // Only used in flex layout, for other layout, it's equivalent to 'start'.
-    case ItemPositionFlexStart:
-    case ItemPositionStart:
-        return startOfRowForChild(child);
-        // Only used in flex layout, for other layout, it's equivalent to 'end'.
-    case ItemPositionFlexEnd:
-    case ItemPositionEnd:
-        return endOfRowForChild(child);
-    case ItemPositionStretch:
-        return startOfRowForChild(child);
-    case ItemPositionBaseline:
-    case ItemPositionLastBaseline:
-        // FIXME: Implement the ItemPositionBaseline value. For now, we always 'start' align the child.
-        return startOfRowForChild(child);
-    case ItemPositionAuto:
-        break;
-    }
-
-    ASSERT_NOT_REACHED();
-    return 0;
-}
-
-ContentPosition static resolveContentDistributionFallback(ContentDistributionType distribution)
-{
-    switch (distribution) {
-    case ContentDistributionSpaceBetween:
-        return ContentPositionStart;
-    case ContentDistributionSpaceAround:
-        return ContentPositionCenter;
-    case ContentDistributionSpaceEvenly:
-        return ContentPositionCenter;
-    case ContentDistributionStretch:
-        return ContentPositionStart;
-    case ContentDistributionDefault:
-        return ContentPositionAuto;
-    }
-
-    ASSERT_NOT_REACHED();
-    return ContentPositionAuto;
-}
-
-static inline LayoutUnit offsetToStartEdge(bool isLeftToRight, LayoutUnit availableSpace)
-{
-    return isLeftToRight ? LayoutUnit(0) : availableSpace;
-}
-
-static inline LayoutUnit offsetToEndEdge(bool isLeftToRight, LayoutUnit availableSpace)
-{
-    return !isLeftToRight ? LayoutUnit(0) : availableSpace;
-}
-
-LayoutUnit RenderGrid::contentPositionAndDistributionColumnOffset(LayoutUnit availableFreeSpace, ContentPosition position, ContentDistributionType distribution, OverflowAlignment overflow, unsigned numberOfGridTracks) const
-{
-    if (overflow == OverflowAlignmentSafe && availableFreeSpace <= 0)
-        return 0;
-
-    // FIXME: for the time being, spec states that it will always fallback for Grids, but
-    // discussion is ongoing.
-    if (distribution != ContentDistributionDefault && position == ContentPositionAuto)
-        position = resolveContentDistributionFallback(distribution);
-
-    switch (position) {
-    case ContentPositionLeft:
-        return 0;
-    case ContentPositionRight:
-        return availableFreeSpace;
-    case ContentPositionCenter:
-        return availableFreeSpace / 2;
-    case ContentPositionFlexEnd:
-        // Only used in flex layout, for other layout, it's equivalent to 'end'.
-    case ContentPositionEnd:
-        return offsetToEndEdge(style()->isLeftToRightDirection(), availableFreeSpace);
-    case ContentPositionFlexStart:
-        // Only used in flex layout, for other layout, it's equivalent to 'start'.
-    case ContentPositionStart:
-        return offsetToStartEdge(style()->isLeftToRightDirection(), availableFreeSpace);
-    case ContentPositionBaseline:
-    case ContentPositionLastBaseline:
-        // FIXME: Implement the previous values. For now, we always 'start' align.
-        // crbug.com/234191
-        return offsetToStartEdge(style()->isLeftToRightDirection(), availableFreeSpace);
-    case ContentPositionAuto:
-        break;
-    }
-
-    ASSERT_NOT_REACHED();
-    return 0;
-}
-
-LayoutUnit RenderGrid::contentPositionAndDistributionRowOffset(LayoutUnit availableFreeSpace, ContentPosition position, ContentDistributionType distribution, OverflowAlignment overflow, unsigned numberOfGridTracks) const
-{
-    if (overflow == OverflowAlignmentSafe && availableFreeSpace <= 0)
-        return 0;
-
-    // FIXME: for the time being, spec states that it will always fallback for Grids, but
-    // discussion is ongoing.
-    if (distribution != ContentDistributionDefault && position == ContentPositionAuto)
-        position = resolveContentDistributionFallback(distribution);
-
-    switch (position) {
-    case ContentPositionLeft:
-        // The align-content's axis is always orthogonal to the inline-axis.
-        return 0;
-    case ContentPositionRight:
-        // The align-content's axis is always orthogonal to the inline-axis.
-        return 0;
-    case ContentPositionCenter:
-        return availableFreeSpace / 2;
-    case ContentPositionFlexEnd:
-        // Only used in flex layout, for other layout, it's equivalent to 'End'.
-    case ContentPositionEnd:
-        return availableFreeSpace;
-    case ContentPositionFlexStart:
-        // Only used in flex layout, for other layout, it's equivalent to 'Start'.
-    case ContentPositionStart:
-        return 0;
-    case ContentPositionBaseline:
-    case ContentPositionLastBaseline:
-        // FIXME: Implement the previous values. For now, we always start align.
-        // crbug.com/234191
-        return 0;
-    case ContentPositionAuto:
-        break;
-    }
-
-    ASSERT_NOT_REACHED();
-    return 0;
-}
-
-LayoutPoint RenderGrid::findChildLogicalPosition(const LayoutBox& child, LayoutSize contentAlignmentOffset) const
-{
-    LayoutUnit columnPosition = columnPositionForChild(child);
-    // We stored m_columnPositions's data ignoring the direction, hence we might need now
-    // to translate positions from RTL to LTR, as it's more convenient for painting.
-    if (!style()->isLeftToRightDirection())
-        columnPosition = (m_columnPositions[m_columnPositions.size() - 1] + borderAndPaddingLogicalLeft()) - columnPosition - child.logicalWidth();
-
-    // The Content Alignment offset accounts for the RTL to LTR flip.
-    LayoutPoint childLocation(columnPosition, rowPositionForChild(child));
-    childLocation.move(contentAlignmentOffset);
-
-    return childLocation;
-}
-
-void RenderGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
-{
-    GridPainter(*this).paintChildren(paintInfo, paintOffset);
-}
-
-const char* RenderGrid::renderName() const
-{
-    if (isFloating())
-        return "RenderGrid (floating)";
-    if (isOutOfFlowPositioned())
-        return "RenderGrid (positioned)";
-    if (isAnonymous())
-        return "RenderGrid (generated)";
-    if (isRelPositioned())
-        return "RenderGrid (relative positioned)";
-    return "RenderGrid";
-}
-
-} // namespace blink