Import Qt5x2 branch of QtWebkit for Qt 5.2

Importing a new snapshot of webkit.

Change-Id: I2d01ad12cdc8af8cb015387641120a9d7ea5f10c
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>

1 files changed, 643 insertions, 63 deletions

diff --git a/Source/WebCore/rendering/RenderGrid.cpp b/Source/WebCore/rendering/RenderGrid.cpp
index e7a351c86..a65941552 100644
--- a/Source/WebCore/rendering/RenderGrid.cpp
+++ b/Source/WebCore/rendering/RenderGrid.cpp
@@ -33,18 +33,101 @@
 
 namespace WebCore {
 
-class RenderGrid::GridTrack {
+static const int infinity = intMaxForLayoutUnit;
+
+class GridTrack {
 public:
     GridTrack()
         : m_usedBreadth(0)
+        , m_maxBreadth(0)
+    {
+    }
+
+    void growUsedBreadth(LayoutUnit growth)
+    {
+        ASSERT(growth >= 0);
+        m_usedBreadth += growth;
+    }
+    LayoutUnit usedBreadth() const { return m_usedBreadth; }
+
+    void growMaxBreadth(LayoutUnit growth)
     {
+        if (m_maxBreadth == infinity)
+            m_maxBreadth = m_usedBreadth + growth;
+        else
+            m_maxBreadth += growth;
+    }
+    LayoutUnit maxBreadthIfNotInfinite() const
+    {
+        return (m_maxBreadth == infinity) ? m_usedBreadth : m_maxBreadth;
     }
 
     LayoutUnit m_usedBreadth;
+    LayoutUnit m_maxBreadth;
+};
+
+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 Vector<Vector<Vector<RenderBox*, 1> > >& grid, TrackSizingDirection direction, size_t fixedTrackIndex)
+        : m_grid(grid)
+        , m_direction(direction)
+        , m_rowIndex((direction == ForColumns) ? 0 : fixedTrackIndex)
+        , m_columnIndex((direction == ForColumns) ? fixedTrackIndex : 0)
+        , m_childIndex(0)
+    {
+        ASSERT(m_rowIndex < m_grid.size());
+        ASSERT(m_columnIndex < m_grid[0].size());
+    }
+
+    RenderBox* nextGridItem()
+    {
+        if (!m_grid.size())
+            return 0;
+
+        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 Vector<RenderBox*>& children = m_grid[m_rowIndex][m_columnIndex];
+            if (m_childIndex < children.size())
+                return children[m_childIndex++];
+
+            m_childIndex = 0;
+        }
+        return 0;
+    }
+
+    PassOwnPtr<GridCoordinate> nextEmptyGridArea()
+    {
+        if (m_grid.isEmpty())
+            return nullptr;
+
+        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 Vector<RenderBox*>& children = m_grid[m_rowIndex][m_columnIndex];
+            if (children.isEmpty()) {
+                OwnPtr<GridCoordinate> result = adoptPtr(new GridCoordinate(GridSpan(m_rowIndex, m_rowIndex), GridSpan(m_columnIndex, m_columnIndex)));
+                // 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 Vector<Vector<Vector<RenderBox*, 1> > >& m_grid;
+    TrackSizingDirection m_direction;
+    size_t m_rowIndex;
+    size_t m_columnIndex;
+    size_t m_childIndex;
 };
 
-RenderGrid::RenderGrid(Node* node)
-    : RenderBlock(node)
+RenderGrid::RenderGrid(Element* element)
+    : RenderBlock(element)
 {
     // All of our children must be block level.
     setChildrenInline(false);
@@ -66,20 +149,18 @@ void RenderGrid::layoutBlock(bool relayoutChildren, LayoutUnit)
     LayoutRepainter repainter(*this, checkForRepaintDuringLayout());
     LayoutStateMaintainer statePusher(view(), this, locationOffset(), hasTransform() || hasReflection() || style()->isFlippedBlocksWritingMode());
 
-    if (inRenderFlowThread()) {
-        // Regions changing widths can force us to relayout our children.
-        if (logicalWidthChangedInRegions())
-            relayoutChildren = true;
-    }
-    updateRegionsAndExclusionsLogicalSize();
+    // Regions changing widths can force us to relayout our children.
+    RenderFlowThread* flowThread = flowThreadContainingBlock();
+    if (logicalWidthChangedInRegions(flowThread))
+        relayoutChildren = true;
+    if (updateRegionsAndShapesBeforeChildLayout(flowThread))
+        relayoutChildren = true;
 
     LayoutSize previousSize = size();
 
     setLogicalHeight(0);
     updateLogicalWidth();
 
-    m_overflow.clear();
-
     layoutGridItems();
 
     LayoutUnit oldClientAfterEdge = clientLogicalBottom();
@@ -90,7 +171,7 @@ void RenderGrid::layoutBlock(bool relayoutChildren, LayoutUnit)
 
     layoutPositionedObjects(relayoutChildren || isRoot());
 
-    computeRegionRangeForBlock();
+    updateRegionsAndShapesAfterChildLayout(flowThread);
 
     computeOverflow(oldClientAfterEdge);
     statePusher.pop();
@@ -99,14 +180,35 @@ void RenderGrid::layoutBlock(bool relayoutChildren, LayoutUnit)
 
     // Update our scroll information if we're overflow:auto/scroll/hidden now that we know if
     // we overflow or not.
-    if (hasOverflowClip())
-        layer()->updateScrollInfoAfterLayout();
+    updateScrollInfoAfterLayout();
 
     repainter.repaintAfterLayout();
 
     setNeedsLayout(false);
 }
 
+void RenderGrid::computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const
+{
+    const_cast<RenderGrid*>(this)->placeItemsOnGrid();
+
+    // FIXME: This is an inefficient way to fill our sizes as it will try every grid areas, when we would
+    // only want to account for fixed grid tracks and grid items. Also this will be incorrect if we have spanning
+    // grid items.
+    for (size_t i = 0; i < gridColumnCount(); ++i) {
+        const GridTrackSize& trackSize = gridTrackSize(ForColumns, i);
+        LayoutUnit minTrackBreadth = computePreferredTrackWidth(trackSize.minTrackBreadth(), i);
+        LayoutUnit maxTrackBreadth = computePreferredTrackWidth(trackSize.maxTrackBreadth(), i);
+        maxTrackBreadth = std::max(maxTrackBreadth, minTrackBreadth);
+
+        minLogicalWidth += minTrackBreadth;
+        maxLogicalWidth += maxTrackBreadth;
+
+        // FIXME: This should add in the scrollbarWidth (e.g. see RenderFlexibleBox).
+    }
+
+    const_cast<RenderGrid*>(this)->clearGrid();
+}
+
 void RenderGrid::computePreferredLogicalWidths()
 {
     ASSERT(preferredLogicalWidthsDirty());
@@ -114,64 +216,471 @@ void RenderGrid::computePreferredLogicalWidths()
     m_minPreferredLogicalWidth = 0;
     m_maxPreferredLogicalWidth = 0;
 
-    // FIXME: We don't take our own logical width into account.
+    // 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.
 
-    const Vector<GridTrackSize>& trackStyles = style()->gridColumns();
+    computeIntrinsicLogicalWidths(m_minPreferredLogicalWidth, m_maxPreferredLogicalWidth);
 
-    for (size_t i = 0; i < trackStyles.size(); ++i) {
-        Length trackLength = trackStyles[i].length();
-        if (!trackLength.isFixed()) {
-            notImplemented();
-            continue;
+    LayoutUnit borderAndPaddingInInlineDirection = borderAndPaddingLogicalWidth();
+    m_minPreferredLogicalWidth += borderAndPaddingInInlineDirection;
+    m_maxPreferredLogicalWidth += borderAndPaddingInInlineDirection;
+
+    setPreferredLogicalWidthsDirty(false);
+}
+
+LayoutUnit RenderGrid::computePreferredTrackWidth(const Length& length, size_t trackIndex) const
+{
+    if (length.isFixed()) {
+        // Grid areas don't have borders, margins or paddings so we don't need to account for them.
+        return length.intValue();
+    }
+
+    if (length.isMinContent()) {
+        LayoutUnit minContentSize = 0;
+        GridIterator iterator(m_grid, ForColumns, trackIndex);
+        while (RenderBox* gridItem = iterator.nextGridItem()) {
+            // FIXME: We should include the child's fixed margins like RenderFlexibleBox.
+            minContentSize = std::max(minContentSize, gridItem->minPreferredLogicalWidth());
         }
+        return minContentSize;
+    }
 
-        m_minPreferredLogicalWidth += trackLength.intValue();
-        m_maxPreferredLogicalWidth += trackLength.intValue();
+    if (length.isMaxContent()) {
+        LayoutUnit maxContentSize = 0;
+        GridIterator iterator(m_grid, ForColumns, trackIndex);
+        while (RenderBox* gridItem = iterator.nextGridItem()) {
+            // FIXME: We should include the child's fixed margins like RenderFlexibleBox.
+            maxContentSize = std::max(maxContentSize, gridItem->maxPreferredLogicalWidth());
+        }
+        return maxContentSize;
     }
 
-    // FIXME: We should account for min / max logical width.
+    // FIXME: css3-sizing mentions that we should resolve "definite sizes"
+    // (including <percentage> and calc()) but we don't do it elsewhere.
+    return 0;
+}
 
-    // FIXME: Include borders and paddings in inline direction.
+void RenderGrid::computedUsedBreadthOfGridTracks(TrackSizingDirection direction, Vector<GridTrack>& columnTracks, Vector<GridTrack>& rowTracks)
+{
+    LayoutUnit availableLogicalSpace = (direction == ForColumns) ? availableLogicalWidth() : availableLogicalHeight(IncludeMarginBorderPadding);
+    Vector<GridTrack>& tracks = (direction == ForColumns) ? columnTracks : rowTracks;
+    for (size_t i = 0; i < tracks.size(); ++i) {
+        GridTrack& track = tracks[i];
+        const GridTrackSize& trackSize = gridTrackSize(direction, i);
+        const Length& minTrackBreadth = trackSize.minTrackBreadth();
+        const Length& maxTrackBreadth = trackSize.maxTrackBreadth();
+
+        track.m_usedBreadth = computeUsedBreadthOfMinLength(direction, minTrackBreadth);
+        track.m_maxBreadth = computeUsedBreadthOfMaxLength(direction, maxTrackBreadth);
+
+        track.m_maxBreadth = std::max(track.m_maxBreadth, track.m_usedBreadth);
+    }
 
-    setPreferredLogicalWidthsDirty(false);
+    // FIXME: We shouldn't call resolveContentBasedTrackSizingFunctions if we have no min-content / max-content tracks.
+    resolveContentBasedTrackSizingFunctions(direction, columnTracks, rowTracks, availableLogicalSpace);
+
+    if (availableLogicalSpace <= 0)
+        return;
+
+    const size_t tracksSize = tracks.size();
+    Vector<GridTrack*> tracksForDistribution(tracksSize);
+    for (size_t i = 0; i < tracksSize; ++i)
+        tracksForDistribution[i] = tracks.data() + i;
+
+    distributeSpaceToTracks(tracksForDistribution, 0, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth, availableLogicalSpace);
+}
+
+LayoutUnit RenderGrid::computeUsedBreadthOfMinLength(TrackSizingDirection direction, const Length& trackLength) const
+{
+    if (trackLength.isFixed() || trackLength.isPercent() || trackLength.isViewportPercentage())
+        return computeUsedBreadthOfSpecifiedLength(direction, trackLength);
+
+    ASSERT(trackLength.isMinContent() || trackLength.isMaxContent() || trackLength.isAuto());
+    return 0;
+}
+
+LayoutUnit RenderGrid::computeUsedBreadthOfMaxLength(TrackSizingDirection direction, const Length& trackLength) const
+{
+    if (trackLength.isFixed() || trackLength.isPercent() || trackLength.isViewportPercentage()) {
+        LayoutUnit computedBreadth = computeUsedBreadthOfSpecifiedLength(direction, trackLength);
+        // FIXME: We should ASSERT that computedBreadth cannot return infinity but it's currently
+        // possible. See https://bugs.webkit.org/show_bug.cgi?id=107053
+        return computedBreadth;
+    }
+
+    ASSERT(trackLength.isMinContent() || trackLength.isMaxContent() || trackLength.isAuto());
+    return infinity;
 }
 
-void RenderGrid::computedUsedBreadthOfGridTracks(TrackSizingDirection direction, Vector<GridTrack>& tracks)
+LayoutUnit RenderGrid::computeUsedBreadthOfSpecifiedLength(TrackSizingDirection direction, const Length& trackLength) const
+{
+    // FIXME: We still need to support calc() here (https://webkit.org/b/103761).
+    ASSERT(trackLength.isFixed() || trackLength.isPercent() || trackLength.isViewportPercentage());
+    return valueForLength(trackLength, direction == ForColumns ? logicalWidth() : computeContentLogicalHeight(style()->logicalHeight()), view());
+}
+
+const GridTrackSize& RenderGrid::gridTrackSize(TrackSizingDirection direction, size_t i) const
+{
+    const Vector<GridTrackSize>& trackStyles = (direction == ForColumns) ? style()->gridColumns() : style()->gridRows();
+    if (i >= trackStyles.size())
+        return (direction == ForColumns) ? style()->gridAutoColumns() : style()->gridAutoRows();
+
+    return trackStyles[i];
+}
+
+static size_t estimatedGridSizeForPosition(const GridPosition& position)
+{
+    if (position.isAuto())
+        return 1;
+
+    return std::max(position.integerPosition(), 1);
+}
+
+size_t RenderGrid::maximumIndexInDirection(TrackSizingDirection direction) const
 {
     const Vector<GridTrackSize>& trackStyles = (direction == ForColumns) ? style()->gridColumns() : style()->gridRows();
-    for (size_t i = 0; i < trackStyles.size(); ++i) {
-        GridTrack track;
-        if (trackStyles[i].length().isFixed())
-            track.m_usedBreadth = trackStyles[i].length().getFloatValue();
-        else
-            notImplemented();
 
-        tracks.append(track);
+    size_t maximumIndex = std::max<size_t>(1, trackStyles.size());
+
+    for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
+        // This function bypasses the cache (cachedGridCoordinate()) as it is used to build it.
+        // Also we can't call resolveGridPositionsFromStyle here as it assumes that the grid is build and we are in
+        // the middle of building it. However we should be able to share more code with the previous logic (FIXME).
+        const GridPosition& initialPosition = (direction == ForColumns) ? child->style()->gridItemStart() : child->style()->gridItemBefore();
+        const GridPosition& finalPosition = (direction == ForColumns) ? child->style()->gridItemEnd() : child->style()->gridItemAfter();
+
+        size_t estimatedSizeForInitialPosition = estimatedGridSizeForPosition(initialPosition);
+        size_t estimatedSizeForFinalPosition = estimatedGridSizeForPosition(finalPosition);
+        ASSERT(estimatedSizeForInitialPosition);
+        ASSERT(estimatedSizeForFinalPosition);
+
+        maximumIndex = std::max(maximumIndex, estimatedSizeForInitialPosition);
+        maximumIndex = std::max(maximumIndex, estimatedSizeForFinalPosition);
+    }
+
+    return maximumIndex;
+}
+
+LayoutUnit RenderGrid::logicalContentHeightForChild(RenderBox* child, Vector<GridTrack>& columnTracks)
+{
+    // FIXME: We shouldn't force a layout every time this function is called but
+    // 1) Return computeLogicalHeight's value if it's available. Unfortunately computeLogicalHeight
+    // doesn't return if the logical height is available so would need to be changed.
+    // 2) Relayout if the column track's used breadth changed OR the logical height is unavailable.
+    if (!child->needsLayout())
+        child->setNeedsLayout(true, MarkOnlyThis);
+
+    child->setOverrideContainingBlockContentLogicalWidth(gridAreaBreadthForChild(child, ForColumns, columnTracks));
+    // 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->layout();
+    return child->logicalHeight();
+}
+
+LayoutUnit RenderGrid::minContentForChild(RenderBox* child, TrackSizingDirection 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();
     }
+
+    return logicalContentHeightForChild(child, columnTracks);
+}
+
+LayoutUnit RenderGrid::maxContentForChild(RenderBox* child, TrackSizingDirection 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();
+    }
+
+    return logicalContentHeightForChild(child, columnTracks);
+}
+
+void RenderGrid::resolveContentBasedTrackSizingFunctions(TrackSizingDirection direction, Vector<GridTrack>& columnTracks, Vector<GridTrack>& rowTracks, LayoutUnit& availableLogicalSpace)
+{
+    // FIXME: Split the grid tracks once we support fractions (step 1 of the algorithm).
+
+    Vector<GridTrack>& tracks = (direction == ForColumns) ? columnTracks : rowTracks;
+
+    // FIXME: Per step 2 of the specification, we should order the grid items by increasing span.
+    for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
+        resolveContentBasedTrackSizingFunctionsForItems(direction, columnTracks, rowTracks, child, &GridTrackSize::hasMinOrMaxContentMinTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth);
+        resolveContentBasedTrackSizingFunctionsForItems(direction, columnTracks, rowTracks, child, &GridTrackSize::hasMaxContentMinTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth);
+        resolveContentBasedTrackSizingFunctionsForItems(direction, columnTracks, rowTracks, child, &GridTrackSize::hasMinOrMaxContentMaxTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::maxBreadthIfNotInfinite, &GridTrack::growMaxBreadth);
+        resolveContentBasedTrackSizingFunctionsForItems(direction, columnTracks, rowTracks, child, &GridTrackSize::hasMaxContentMaxTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::maxBreadthIfNotInfinite, &GridTrack::growMaxBreadth);
+    }
+
+    for (size_t i = 0; i < tracks.size(); ++i) {
+        GridTrack& track = tracks[i];
+        if (track.m_maxBreadth == infinity)
+            track.m_maxBreadth = track.m_usedBreadth;
+
+        availableLogicalSpace -= track.m_usedBreadth;
+    }
+}
+
+void RenderGrid::resolveContentBasedTrackSizingFunctionsForItems(TrackSizingDirection direction, Vector<GridTrack>& columnTracks, Vector<GridTrack>& rowTracks, RenderBox* gridItem, FilterFunction filterFunction, SizingFunction sizingFunction, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction)
+{
+    const GridCoordinate coordinate = cachedGridCoordinate(gridItem);
+    const size_t initialTrackIndex = (direction == ForColumns) ? coordinate.columns.initialPositionIndex : coordinate.rows.initialPositionIndex;
+    const size_t finalTrackIndex = (direction == ForColumns) ? coordinate.columns.finalPositionIndex : coordinate.rows.finalPositionIndex;
+
+    Vector<GridTrack*> tracks;
+    for (size_t trackIndex = initialTrackIndex; trackIndex <= finalTrackIndex; ++trackIndex) {
+        const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex);
+        if (!(trackSize.*filterFunction)())
+            continue;
+
+        GridTrack& track = (direction == ForColumns) ? columnTracks[trackIndex] : rowTracks[trackIndex];
+        tracks.append(&track);
+    }
+
+    LayoutUnit additionalBreadthSpace = (this->*sizingFunction)(gridItem, direction, columnTracks);
+    for (size_t trackIndexForSpace = initialTrackIndex; trackIndexForSpace <= finalTrackIndex; ++trackIndexForSpace) {
+        GridTrack& track = (direction == ForColumns) ? columnTracks[trackIndexForSpace] : rowTracks[trackIndexForSpace];
+        additionalBreadthSpace -= (track.*trackGetter)();
+    }
+
+    // FIXME: We should pass different values for |tracksForGrowthAboveMaxBreadth|.
+    distributeSpaceToTracks(tracks, &tracks, trackGetter, trackGrowthFunction, additionalBreadthSpace);
+}
+
+static bool sortByGridTrackGrowthPotential(const GridTrack* track1, const GridTrack* track2)
+{
+    return (track1->m_maxBreadth - track1->m_usedBreadth) < (track2->m_maxBreadth - track2->m_usedBreadth);
+}
+
+void RenderGrid::distributeSpaceToTracks(Vector<GridTrack*>& tracks, Vector<GridTrack*>* tracksForGrowthAboveMaxBreadth, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction, LayoutUnit& availableLogicalSpace)
+{
+    std::sort(tracks.begin(), tracks.end(), sortByGridTrackGrowthPotential);
+
+    size_t tracksSize = tracks.size();
+    Vector<LayoutUnit> updatedTrackBreadths(tracksSize);
+
+    for (size_t i = 0; i < tracksSize; ++i) {
+        GridTrack& track = *tracks[i];
+        LayoutUnit availableLogicalSpaceShare = availableLogicalSpace / (tracksSize - i);
+        LayoutUnit trackBreadth = (tracks[i]->*trackGetter)();
+        LayoutUnit growthShare = std::min(availableLogicalSpaceShare, track.m_maxBreadth - trackBreadth);
+        updatedTrackBreadths[i] = trackBreadth + growthShare;
+        availableLogicalSpace -= growthShare;
+    }
+
+    if (availableLogicalSpace > 0 && tracksForGrowthAboveMaxBreadth) {
+        tracksSize = tracksForGrowthAboveMaxBreadth->size();
+        for (size_t i = 0; i < tracksSize; ++i) {
+            LayoutUnit growthShare = availableLogicalSpace / (tracksSize - i);
+            updatedTrackBreadths[i] += growthShare;
+            availableLogicalSpace -= growthShare;
+        }
+    }
+
+    for (size_t i = 0; i < tracksSize; ++i) {
+        LayoutUnit growth = updatedTrackBreadths[i] - (tracks[i]->*trackGetter)();
+        if (growth >= 0)
+            (tracks[i]->*trackGrowthFunction)(growth);
+    }
+}
+
+#ifndef NDEBUG
+bool RenderGrid::tracksAreWiderThanMinTrackBreadth(TrackSizingDirection direction, const Vector<GridTrack>& tracks)
+{
+    for (size_t i = 0; i < tracks.size(); ++i) {
+        const GridTrackSize& trackSize = gridTrackSize(direction, i);
+        const Length& minTrackBreadth = trackSize.minTrackBreadth();
+        if (computeUsedBreadthOfMinLength(direction, minTrackBreadth) > tracks[i].m_usedBreadth)
+            return false;
+    }
+    return true;
+}
+#endif
+
+void RenderGrid::growGrid(TrackSizingDirection direction)
+{
+    if (direction == ForColumns) {
+        const size_t oldColumnSize = m_grid[0].size();
+        for (size_t row = 0; row < m_grid.size(); ++row)
+            m_grid[row].grow(oldColumnSize + 1);
+    } else {
+        const size_t oldRowSize = m_grid.size();
+        m_grid.grow(oldRowSize + 1);
+        m_grid[oldRowSize].grow(m_grid[0].size());
+    }
+}
+
+void RenderGrid::insertItemIntoGrid(RenderBox* child, const GridCoordinate& coordinate)
+{
+    m_grid[coordinate.rows.initialPositionIndex][coordinate.columns.initialPositionIndex].append(child);
+    m_gridItemCoordinate.set(child, coordinate);
+}
+
+void RenderGrid::insertItemIntoGrid(RenderBox* child, size_t rowTrack, size_t columnTrack)
+{
+    const GridSpan& rowSpan = resolveGridPositionsFromAutoPlacementPosition(child, ForRows, rowTrack);
+    const GridSpan& columnSpan = resolveGridPositionsFromAutoPlacementPosition(child, ForColumns, columnTrack);
+    insertItemIntoGrid(child, GridCoordinate(rowSpan, columnSpan));
+}
+
+void RenderGrid::placeItemsOnGrid()
+{
+    ASSERT(!gridWasPopulated());
+    ASSERT(m_gridItemCoordinate.isEmpty());
+
+    m_grid.grow(maximumIndexInDirection(ForRows));
+    size_t maximumColumnIndex = maximumIndexInDirection(ForColumns);
+    for (size_t i = 0; i < m_grid.size(); ++i)
+        m_grid[i].grow(maximumColumnIndex);
+
+    Vector<RenderBox*> autoMajorAxisAutoGridItems;
+    Vector<RenderBox*> specifiedMajorAxisAutoGridItems;
+    GridAutoFlow autoFlow = style()->gridAutoFlow();
+    for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
+        // FIXME: We never re-resolve positions if the grid is grown during auto-placement which may lead auto / <integer>
+        // positions to not match the author's intent. The specification is unclear on what should be done in this case.
+        OwnPtr<GridSpan> rowPositions = resolveGridPositionsFromStyle(child, ForRows);
+        OwnPtr<GridSpan> columnPositions = resolveGridPositionsFromStyle(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() >= style()->gridRows().size());
+    ASSERT(gridColumnCount() >= style()->gridColumns().size());
+
+    if (autoFlow == AutoFlowNone) {
+        // If we did collect some grid items, they won't be placed thus never laid out.
+        ASSERT(!autoMajorAxisAutoGridItems.size());
+        ASSERT(!specifiedMajorAxisAutoGridItems.size());
+        return;
+    }
+
+    placeSpecifiedMajorAxisItemsOnGrid(specifiedMajorAxisAutoGridItems);
+    placeAutoMajorAxisItemsOnGrid(autoMajorAxisAutoGridItems);
+}
+
+void RenderGrid::placeSpecifiedMajorAxisItemsOnGrid(Vector<RenderBox*> autoGridItems)
+{
+    for (size_t i = 0; i < autoGridItems.size(); ++i) {
+        OwnPtr<GridSpan> majorAxisPositions = resolveGridPositionsFromStyle(autoGridItems[i], autoPlacementMajorAxisDirection());
+        GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions->initialPositionIndex);
+        if (OwnPtr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea()) {
+            insertItemIntoGrid(autoGridItems[i], emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
+            continue;
+        }
+
+        growGrid(autoPlacementMinorAxisDirection());
+        OwnPtr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea();
+        ASSERT(emptyGridArea);
+        insertItemIntoGrid(autoGridItems[i], emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
+    }
+}
+
+void RenderGrid::placeAutoMajorAxisItemsOnGrid(Vector<RenderBox*> autoGridItems)
+{
+    for (size_t i = 0; i < autoGridItems.size(); ++i)
+        placeAutoMajorAxisItemOnGrid(autoGridItems[i]);
+}
+
+void RenderGrid::placeAutoMajorAxisItemOnGrid(RenderBox* gridItem)
+{
+    OwnPtr<GridSpan> minorAxisPositions = resolveGridPositionsFromStyle(gridItem, autoPlacementMinorAxisDirection());
+    ASSERT(!resolveGridPositionsFromStyle(gridItem, autoPlacementMajorAxisDirection()));
+    size_t minorAxisIndex = 0;
+    if (minorAxisPositions) {
+        minorAxisIndex = minorAxisPositions->initialPositionIndex;
+        GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisIndex);
+        if (OwnPtr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea()) {
+            insertItemIntoGrid(gridItem, emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
+            return;
+        }
+    } else {
+        const size_t endOfMajorAxis = (autoPlacementMajorAxisDirection() == ForColumns) ? gridColumnCount() : gridRowCount();
+        for (size_t majorAxisIndex = 0; majorAxisIndex < endOfMajorAxis; ++majorAxisIndex) {
+            GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisIndex);
+            if (OwnPtr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea()) {
+                insertItemIntoGrid(gridItem, emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
+                return;
+            }
+        }
+    }
+
+    // We didn't find an empty grid area so we need to create an extra major axis line and insert our gridItem in it.
+    const size_t columnIndex = (autoPlacementMajorAxisDirection() == ForColumns) ? m_grid[0].size() : minorAxisIndex;
+    const size_t rowIndex = (autoPlacementMajorAxisDirection() == ForColumns) ? minorAxisIndex : m_grid.size();
+    growGrid(autoPlacementMajorAxisDirection());
+    insertItemIntoGrid(gridItem, rowIndex, columnIndex);
+}
+
+RenderGrid::TrackSizingDirection RenderGrid::autoPlacementMajorAxisDirection() const
+{
+    GridAutoFlow flow = style()->gridAutoFlow();
+    ASSERT(flow != AutoFlowNone);
+    return (flow == AutoFlowColumn) ? ForColumns : ForRows;
+}
+
+RenderGrid::TrackSizingDirection RenderGrid::autoPlacementMinorAxisDirection() const
+{
+    GridAutoFlow flow = style()->gridAutoFlow();
+    ASSERT(flow != AutoFlowNone);
+    return (flow == AutoFlowColumn) ? ForRows : ForColumns;
+}
+
+void RenderGrid::clearGrid()
+{
+    m_grid.clear();
+    m_gridItemCoordinate.clear();
 }
 
 void RenderGrid::layoutGridItems()
 {
-    Vector<GridTrack> columnTracks, rowTracks;
-    computedUsedBreadthOfGridTracks(ForColumns, columnTracks);
-    // FIXME: The logical width of Grid Columns from the prior step is used in
-    // the formatting of Grid items in content-sized Grid Rows to determine
-    // their required height. We will probably need to pass columns through.
-    computedUsedBreadthOfGridTracks(ForRows, rowTracks);
+    placeItemsOnGrid();
+
+    Vector<GridTrack> columnTracks(gridColumnCount());
+    Vector<GridTrack> rowTracks(gridRowCount());
+    computedUsedBreadthOfGridTracks(ForColumns, columnTracks, rowTracks);
+    ASSERT(tracksAreWiderThanMinTrackBreadth(ForColumns, columnTracks));
+    computedUsedBreadthOfGridTracks(ForRows, columnTracks, rowTracks);
+    ASSERT(tracksAreWiderThanMinTrackBreadth(ForRows, rowTracks));
 
     for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
         LayoutPoint childPosition = findChildLogicalPosition(child, columnTracks, rowTracks);
 
-        size_t columnTrack = resolveGridPosition(child->style()->gridItemColumn());
-        size_t rowTrack = resolveGridPosition(child->style()->gridItemRow());
+        // 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();
 
-        // FIXME: Properly support implicit rows and columns (bug 103573).
-        if (columnTrack < columnTracks.size() && rowTrack < rowTracks.size()) {
-            // Because the grid area cannot be styled, we don't need to adjust
-            // the grid breadth to account for 'box-sizing'.
-            child->setOverrideContainingBlockContentLogicalWidth(columnTracks[columnTrack].m_usedBreadth);
-            child->setOverrideContainingBlockContentLogicalHeight(rowTracks[rowTrack].m_usedBreadth);
-        }
+        // FIXME: For children in a content sized track, we clear the overrideContainingBlockContentLogicalHeight
+        // in minContentForChild / maxContentForChild which means that we will always relayout the child.
+        LayoutUnit overrideContainingBlockContentLogicalWidth = gridAreaBreadthForChild(child, ForColumns, columnTracks);
+        LayoutUnit overrideContainingBlockContentLogicalHeight = gridAreaBreadthForChild(child, ForRows, rowTracks);
+        if (oldOverrideContainingBlockContentLogicalWidth != overrideContainingBlockContentLogicalWidth || oldOverrideContainingBlockContentLogicalHeight != overrideContainingBlockContentLogicalHeight)
+            child->setNeedsLayout(true, MarkOnlyThis);
+
+        child->setOverrideContainingBlockContentLogicalWidth(overrideContainingBlockContentLogicalWidth);
+        child->setOverrideContainingBlockContentLogicalHeight(overrideContainingBlockContentLogicalHeight);
+
+        LayoutRect oldChildRect = child->frameRect();
 
         // FIXME: Grid items should stretch to fill their cells. Once we
         // implement grid-{column,row}-align, we can also shrink to fit. For
@@ -180,43 +689,114 @@ void RenderGrid::layoutGridItems()
 
         // FIXME: Handle border & padding on the grid element.
         child->setLogicalLocation(childPosition);
+
+        // If the child moved, we have to repaint it as well as any floating/positioned
+        // descendants. An exception is if we need a layout. In this case, we know we're going to
+        // repaint ourselves (and the child) anyway.
+        if (!selfNeedsLayout() && child->checkForRepaintDuringLayout())
+            child->repaintDuringLayoutIfMoved(oldChildRect);
     }
 
-    // FIXME: Handle border & padding on the grid element.
     for (size_t i = 0; i < rowTracks.size(); ++i)
         setLogicalHeight(logicalHeight() + rowTracks[i].m_usedBreadth);
+
+    // FIXME: We should handle min / max logical height.
+
+    setLogicalHeight(logicalHeight() + borderAndPaddingLogicalHeight());
+    clearGrid();
+}
+
+RenderGrid::GridCoordinate RenderGrid::cachedGridCoordinate(const RenderBox* gridItem) const
+{
+    ASSERT(m_gridItemCoordinate.contains(gridItem));
+    return m_gridItemCoordinate.get(gridItem);
+}
+
+RenderGrid::GridSpan RenderGrid::resolveGridPositionsFromAutoPlacementPosition(const RenderBox*, TrackSizingDirection, size_t initialPosition) const
+{
+    // FIXME: We don't support spanning with auto positions yet. Once we do, this is wrong. Also we should make
+    // sure the grid can accomodate the new item as we only grow 1 position in a given direction.
+    return GridSpan(initialPosition, initialPosition);
 }
 
-size_t RenderGrid::resolveGridPosition(const GridPosition& position) const
+PassOwnPtr<RenderGrid::GridSpan> RenderGrid::resolveGridPositionsFromStyle(const RenderBox* gridItem, TrackSizingDirection direction) const
 {
+    ASSERT(gridWasPopulated());
+
+    const GridPosition& initialPosition = (direction == ForColumns) ? gridItem->style()->gridItemStart() : gridItem->style()->gridItemBefore();
+    const GridPositionSide initialPositionSide = (direction == ForColumns) ? StartSide : BeforeSide;
+    const GridPosition& finalPosition = (direction == ForColumns) ? gridItem->style()->gridItemEnd() : gridItem->style()->gridItemAfter();
+    const GridPositionSide finalPositionSide = (direction == ForColumns) ? EndSide : AfterSide;
+
+    if (initialPosition.isAuto() && finalPosition.isAuto()) {
+        if (style()->gridAutoFlow() == AutoFlowNone)
+            return adoptPtr(new GridSpan(0, 0));
+
+        // We can't get our grid positions without running the auto placement algorithm.
+        return nullptr;
+    }
+
+    if (initialPosition.isAuto()) {
+        // Infer the position from the final position ('auto / 1' case).
+        const size_t finalResolvedPosition = resolveGridPositionFromStyle(finalPosition, finalPositionSide);
+        return adoptPtr(new GridSpan(finalResolvedPosition, finalResolvedPosition));
+    }
+
+    if (finalPosition.isAuto()) {
+        // Infer our position from the initial position ('1 / auto' case).
+        const size_t initialResolvedPosition = resolveGridPositionFromStyle(initialPosition, initialPositionSide);
+        return adoptPtr(new GridSpan(initialResolvedPosition, initialResolvedPosition));
+    }
+
+    return adoptPtr(new GridSpan(resolveGridPositionFromStyle(initialPosition, initialPositionSide), resolveGridPositionFromStyle(finalPosition, finalPositionSide)));
+}
+
+size_t RenderGrid::resolveGridPositionFromStyle(const GridPosition& position, GridPositionSide side) const
+{
+    ASSERT(gridWasPopulated());
+
     // FIXME: Handle other values for grid-{row,column} like ranges or line names.
     switch (position.type()) {
-    case IntegerPosition:
+    case IntegerPosition: {
         // FIXME: What does a non-positive integer mean for a column/row?
-        if (!position.isPositive())
-            return 0;
+        size_t resolvedPosition = position.isPositive() ? position.integerPosition() - 1 : 0;
+
+        if (side == StartSide || side == BeforeSide)
+            return resolvedPosition;
 
-        return position.integerPosition() - 1;
+        const size_t endOfTrack = (side == EndSide) ? gridColumnCount() - 1 : gridRowCount() - 1;
+        ASSERT(endOfTrack >= resolvedPosition);
+        return endOfTrack - resolvedPosition;
+    }
     case AutoPosition:
-        // FIXME: We should follow 'grid-auto-flow' for resolution.
-        // Until then, we use the 'grid-auto-flow: none' behavior (which is the default)
-        // and resolve 'auto' as the first row / column.
+        // 'auto' depends on the opposite position for resolution (e.g. grid-row: auto / 1).
+        ASSERT_NOT_REACHED();
         return 0;
     }
     ASSERT_NOT_REACHED();
     return 0;
 }
 
+LayoutUnit RenderGrid::gridAreaBreadthForChild(const RenderBox* child, TrackSizingDirection direction, const Vector<GridTrack>& tracks) const
+{
+    const GridCoordinate& coordinate = cachedGridCoordinate(child);
+    const GridSpan& span = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
+    LayoutUnit gridAreaBreadth = 0;
+    for (size_t trackIndex = span.initialPositionIndex; trackIndex <= span.finalPositionIndex; ++trackIndex)
+        gridAreaBreadth += tracks[trackIndex].m_usedBreadth;
+    return gridAreaBreadth;
+}
+
 LayoutPoint RenderGrid::findChildLogicalPosition(RenderBox* child, const Vector<GridTrack>& columnTracks, const Vector<GridTrack>& rowTracks)
 {
-    size_t columnTrack = resolveGridPosition(child->style()->gridItemColumn());
-    size_t rowTrack = resolveGridPosition(child->style()->gridItemRow());
+    const GridCoordinate& coordinate = cachedGridCoordinate(child);
 
-    LayoutPoint offset;
+    // The grid items should be inside the grid container's border box, that's why they need to be shifted.
+    LayoutPoint offset(borderAndPaddingStart(), borderAndPaddingBefore());
     // FIXME: |columnTrack| and |rowTrack| should be smaller than our column / row count.
-    for (size_t i = 0; i < columnTrack && i < columnTracks.size(); ++i)
+    for (size_t i = 0; i < coordinate.columns.initialPositionIndex && i < columnTracks.size(); ++i)
         offset.setX(offset.x() + columnTracks[i].m_usedBreadth);
-    for (size_t i = 0; i < rowTrack && i < rowTracks.size(); ++i)
+    for (size_t i = 0; i < coordinate.rows.initialPositionIndex && i < rowTracks.size(); ++i)
         offset.setY(offset.y() + rowTracks[i].m_usedBreadth);
 
     // FIXME: Handle margins on the grid item.