[css-grid] Cache definite height detection

This is a refactoring patch which stores the definite/indefinite height
detection in a new attribute m_hasDefiniteLogicalHeight in LayoutGrid.
That way we just only call LayoutBlock::hasDefiniteLogicalHeight() once,
from LayoutGrid::layoutBlock(). Then in LayoutGrid::gridTrackSize()
we reuse the cached value.

No new tests, no change of behavior.

BUG=624301

Review-Url: https://codereview.chromium.org/2334133002
Cr-Commit-Position: refs/heads/master@{#418831}

third_party/WebKit/Source/core/layout/LayoutGrid.cpp

@@ -453,7 +453,7 @@ void LayoutGrid::layoutBlock(bool relayoutChildren)
         LayoutSize previousSize = size();
 
         updateLogicalWidth();
-        bool logicalHeightWasIndefinite = !hasDefiniteLogicalHeight();
+        m_hasDefiniteLogicalHeight = hasDefiniteLogicalHeight();
 
         TextAutosizer::LayoutScope textAutosizerLayoutScope(this, &layoutScope);
 
@@ -475,10 +475,10 @@ void LayoutGrid::layoutBlock(bool relayoutChildren)
 
         // 2- Next, the track sizing algorithm resolves the sizes of the grid rows, using the
         // grid column sizes calculated in the previous step.
-        if (logicalHeightWasIndefinite)
-            computeIntrinsicLogicalHeight(sizingData);
-        else
+        if (cachedHasDefiniteLogicalHeight())
             computeTrackSizesForDirection(ForRows, sizingData, availableLogicalHeight(ExcludeMarginBorderPadding));
+        else
+            computeIntrinsicLogicalHeight(sizingData);
         setLogicalHeight(computeTrackBasedLogicalHeight(sizingData) + borderAndPaddingLogicalHeight() + scrollbarLogicalHeight());
 
         LayoutUnit oldClientAfterEdge = clientLogicalBottom();
@@ -487,7 +487,7 @@ void LayoutGrid::layoutBlock(bool relayoutChildren)
         // The above call might have changed the grid's logical height depending on min|max height restrictions.
         // Update the sizes of the rows whose size depends on the logical height (also on definite|indefinite sizes).
         LayoutUnit availableSpaceForRows = contentLogicalHeight();
-        if (logicalHeightWasIndefinite)
+        if (!cachedHasDefiniteLogicalHeight())
             computeTrackSizesForDirection(ForRows, sizingData, availableSpaceForRows);
 
         // 3- If the min-content contribution of any grid items have changed based on the row
@@ -929,7 +929,7 @@ GridTrackSize LayoutGrid::gridTrackSize(GridTrackSizingDirection direction, size
     // If the logical width/height of the grid container is indefinite, percentage values are treated as <auto>.
     if (minTrackBreadth.hasPercentage() || maxTrackBreadth.hasPercentage()) {
         // For the inline axis this only happens when we're computing the intrinsic sizes (AvailableSpaceIndefinite).
-        if ((sizingOperation == IntrinsicSizeComputation) || (direction == ForRows && !hasDefiniteLogicalHeight())) {
+        if ((sizingOperation == IntrinsicSizeComputation) || (direction == ForRows && !cachedHasDefiniteLogicalHeight())) {
             if (minTrackBreadth.hasPercentage())
                 minTrackBreadth = Length(Auto);
             if (maxTrackBreadth.hasPercentage())
@@ -2672,4 +2672,10 @@ void LayoutGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& pa
         GridPainter(*this).paintChildren(paintInfo, paintOffset);
 }
 
+bool LayoutGrid::cachedHasDefiniteLogicalHeight() const
+{
+    SECURITY_DCHECK(m_hasDefiniteLogicalHeight);
+    return m_hasDefiniteLogicalHeight.value();
+}
+
 } // namespace blink

third_party/WebKit/Source/core/layout/LayoutGrid.h

@@ -220,6 +220,8 @@ private:
     bool isOrthogonalChild(const LayoutBox&) const;
     GridTrackSizingDirection flowAwareDirectionForChild(const LayoutBox&, GridTrackSizingDirection) const;
 
+    bool cachedHasDefiniteLogicalHeight() const;
+
     typedef Vector<Vector<GridCell>> GridRepresentation;
     GridRepresentation m_grid;
     bool m_gridIsDirty;
@@ -245,6 +247,8 @@ private:
 
     std::unique_ptr<OrderedTrackIndexSet> m_autoRepeatEmptyColumns { nullptr };
     std::unique_ptr<OrderedTrackIndexSet> m_autoRepeatEmptyRows { nullptr };
+
+    Optional<bool> m_hasDefiniteLogicalHeight;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutGrid, isLayoutGrid());