[css-grid] Rename GridSpan properties
https://bugs.webkit.org/show_bug.cgi?id=155636

Reviewed by Sergio Villar Senin.

GridSpan was using old names initialResolvedPosition and
finalResolvedPosition.
This patch rename them to startLine and endLine.

Some reasons for this refactoring:
- "position" is a vague term not defined in the spec.
- GridSpan is currently storing grid lines. A grid "line" is defined
  in the spec: https://drafts.csswg.org/css-grid/#grid-line-concept
- The spec uses the concepts "start" and "end" lines too.

No new tests, no change of behavior.

* css/CSSGridTemplateAreasValue.cpp:
(WebCore::stringForPosition):
* css/CSSParser.cpp:
(WebCore::CSSParser::parseGridTemplateAreasRow):
* css/StyleBuilderConverter.h:
(WebCore::StyleBuilderConverter::createImplicitNamedGridLinesFromGridArea):
* rendering/RenderGrid.cpp:
(WebCore::RenderGrid::computeUsedBreadthOfGridTracks):
(WebCore::RenderGrid::resolveContentBasedTrackSizingFunctionsForNonSpanningItems):
(WebCore::RenderGrid::insertItemIntoGrid):
(WebCore::RenderGrid::populateExplicitGridAndOrderIterator):
(WebCore::RenderGrid::placeSpecifiedMajorAxisItemsOnGrid):
(WebCore::RenderGrid::placeAutoMajorAxisItemOnGrid):
(WebCore::RenderGrid::offsetAndBreadthForPositionedChild):
(WebCore::RenderGrid::gridAreaBreadthForChildIncludingAlignmentOffsets):
(WebCore::RenderGrid::columnAxisOffsetForChild):
(WebCore::RenderGrid::rowAxisOffsetForChild):
* rendering/style/GridArea.h:
(WebCore::GridSpan::untranslatedDefiniteGridSpan):
(WebCore::GridSpan::translatedDefiniteGridSpan):
(WebCore::GridSpan::operator==):
(WebCore::GridSpan::integerSpan):
(WebCore::GridSpan::untranslatedStartLine):
(WebCore::GridSpan::untranslatedEndLine):
(WebCore::GridSpan::startLine):
(WebCore::GridSpan::endLine):
(WebCore::GridSpan::begin):
(WebCore::GridSpan::end):
(WebCore::GridSpan::translate):
(WebCore::GridSpan::GridSpan):
(WebCore::GridSpan::untranslatedResolvedInitialPosition): Deleted.
(WebCore::GridSpan::untranslatedResolvedFinalPosition): Deleted.
(WebCore::GridSpan::resolvedInitialPosition): Deleted.
(WebCore::GridSpan::resolvedFinalPosition): Deleted.
* rendering/style/GridPositionsResolver.cpp:
(WebCore::definiteGridSpanWithNamedLineSpanAgainstOpposite):
(WebCore::resolveNamedGridLinePositionAgainstOppositePosition):
(WebCore::resolveGridPositionAgainstOppositePosition):
(WebCore::GridPositionsResolver::resolveGridPositionsFromStyle):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@198399 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index 6500af9..2b76328 100644
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,62 @@
+2016-03-18  Manuel Rego Casasnovas  <rego@igalia.com>
+
+        [css-grid] Rename GridSpan properties
+        https://bugs.webkit.org/show_bug.cgi?id=155636
+
+        Reviewed by Sergio Villar Senin.
+
+        GridSpan was using old names initialResolvedPosition and
+        finalResolvedPosition.
+        This patch rename them to startLine and endLine.
+
+        Some reasons for this refactoring:
+        - "position" is a vague term not defined in the spec.
+        - GridSpan is currently storing grid lines. A grid "line" is defined
+          in the spec: https://drafts.csswg.org/css-grid/#grid-line-concept
+        - The spec uses the concepts "start" and "end" lines too.
+
+        No new tests, no change of behavior.
+
+        * css/CSSGridTemplateAreasValue.cpp:
+        (WebCore::stringForPosition):
+        * css/CSSParser.cpp:
+        (WebCore::CSSParser::parseGridTemplateAreasRow):
+        * css/StyleBuilderConverter.h:
+        (WebCore::StyleBuilderConverter::createImplicitNamedGridLinesFromGridArea):
+        * rendering/RenderGrid.cpp:
+        (WebCore::RenderGrid::computeUsedBreadthOfGridTracks):
+        (WebCore::RenderGrid::resolveContentBasedTrackSizingFunctionsForNonSpanningItems):
+        (WebCore::RenderGrid::insertItemIntoGrid):
+        (WebCore::RenderGrid::populateExplicitGridAndOrderIterator):
+        (WebCore::RenderGrid::placeSpecifiedMajorAxisItemsOnGrid):
+        (WebCore::RenderGrid::placeAutoMajorAxisItemOnGrid):
+        (WebCore::RenderGrid::offsetAndBreadthForPositionedChild):
+        (WebCore::RenderGrid::gridAreaBreadthForChildIncludingAlignmentOffsets):
+        (WebCore::RenderGrid::columnAxisOffsetForChild):
+        (WebCore::RenderGrid::rowAxisOffsetForChild):
+        * rendering/style/GridArea.h:
+        (WebCore::GridSpan::untranslatedDefiniteGridSpan):
+        (WebCore::GridSpan::translatedDefiniteGridSpan):
+        (WebCore::GridSpan::operator==):
+        (WebCore::GridSpan::integerSpan):
+        (WebCore::GridSpan::untranslatedStartLine):
+        (WebCore::GridSpan::untranslatedEndLine):
+        (WebCore::GridSpan::startLine):
+        (WebCore::GridSpan::endLine):
+        (WebCore::GridSpan::begin):
+        (WebCore::GridSpan::end):
+        (WebCore::GridSpan::translate):
+        (WebCore::GridSpan::GridSpan):
+        (WebCore::GridSpan::untranslatedResolvedInitialPosition): Deleted.
+        (WebCore::GridSpan::untranslatedResolvedFinalPosition): Deleted.
+        (WebCore::GridSpan::resolvedInitialPosition): Deleted.
+        (WebCore::GridSpan::resolvedFinalPosition): Deleted.
+        * rendering/style/GridPositionsResolver.cpp:
+        (WebCore::definiteGridSpanWithNamedLineSpanAgainstOpposite):
+        (WebCore::resolveNamedGridLinePositionAgainstOppositePosition):
+        (WebCore::resolveGridPositionAgainstOppositePosition):
+        (WebCore::GridPositionsResolver::resolveGridPositionsFromStyle):
+
 2016-03-18  Csaba Osztrogonác  <ossy@webkit.org>
 
         [Mac][cmake] One more unreviewed speculative buildfix after r197633. Just for fun.
diff --git a/Source/WebCore/css/CSSGridTemplateAreasValue.cpp b/Source/WebCore/css/CSSGridTemplateAreasValue.cpp
index 63f6697..909398e 100644
--- a/Source/WebCore/css/CSSGridTemplateAreasValue.cpp
+++ b/Source/WebCore/css/CSSGridTemplateAreasValue.cpp
@@ -55,13 +55,13 @@
 
     for (const auto& it : gridAreaMap) {
         const GridArea& area = it.value;
-        if (row >= area.rows.resolvedInitialPosition() && row < area.rows.resolvedFinalPosition())
+        if (row >= area.rows.startLine() && row < area.rows.endLine())
             candidates.append(it.key);
     }
 
     for (const auto& it : gridAreaMap) {
         const GridArea& area = it.value;
-        if (column >= area.columns.resolvedInitialPosition() && column < area.columns.resolvedFinalPosition() && candidates.contains(it.key))
+        if (column >= area.columns.startLine() && column < area.columns.endLine() && candidates.contains(it.key))
             return it.key;
     }
 
diff --git a/Source/WebCore/css/CSSParser.cpp b/Source/WebCore/css/CSSParser.cpp
index 27e6a39..496f4f9 100644
--- a/Source/WebCore/css/CSSParser.cpp
+++ b/Source/WebCore/css/CSSParser.cpp
@@ -6255,18 +6255,18 @@
 
             // The following checks test that the grid area is a single filled-in rectangle.
             // 1. The new row is adjacent to the previously parsed row.
-            if (rowCount != gridArea.rows.resolvedFinalPosition())
+            if (rowCount != gridArea.rows.endLine())
                 return false;
 
             // 2. The new area starts at the same position as the previously parsed area.
-            if (currentColumn != gridArea.columns.resolvedInitialPosition())
+            if (currentColumn != gridArea.columns.startLine())
                 return false;
 
             // 3. The new area ends at the same position as the previously parsed area.
-            if (lookAheadColumn != gridArea.columns.resolvedFinalPosition())
+            if (lookAheadColumn != gridArea.columns.endLine())
                 return false;
 
-            gridArea.rows = GridSpan::translatedDefiniteGridSpan(gridArea.rows.resolvedInitialPosition(), gridArea.rows.resolvedFinalPosition() + 1);
+            gridArea.rows = GridSpan::translatedDefiniteGridSpan(gridArea.rows.startLine(), gridArea.rows.endLine() + 1);
         }
         currentColumn = lookAheadColumn - 1;
     }
diff --git a/Source/WebCore/css/StyleBuilderConverter.h b/Source/WebCore/css/StyleBuilderConverter.h
index b3d7839..ef6b19d 100644
--- a/Source/WebCore/css/StyleBuilderConverter.h
+++ b/Source/WebCore/css/StyleBuilderConverter.h
@@ -939,12 +939,12 @@
         GridSpan areaSpan = direction == ForRows ? area.value.rows : area.value.columns;
         {
             auto& startVector = namedGridLines.add(area.key + "-start", Vector<unsigned>()).iterator->value;
-            startVector.append(areaSpan.resolvedInitialPosition());
+            startVector.append(areaSpan.startLine());
             std::sort(startVector.begin(), startVector.end());
         }
         {
             auto& endVector = namedGridLines.add(area.key + "-end", Vector<unsigned>()).iterator->value;
-            endVector.append(areaSpan.resolvedFinalPosition());
+            endVector.append(areaSpan.endLine());
             std::sort(endVector.begin(), endVector.end());
         }
     }
diff --git a/Source/WebCore/rendering/RenderGrid.cpp b/Source/WebCore/rendering/RenderGrid.cpp
index 5788a01..4ce9571 100644
--- a/Source/WebCore/rendering/RenderGrid.cpp
+++ b/Source/WebCore/rendering/RenderGrid.cpp
@@ -578,7 +578,7 @@
                 const GridSpan span = cachedGridSpan(*gridItem, direction);
 
                 // Do not include already processed items.
-                if (i > 0 && span.resolvedInitialPosition() <= flexibleSizedTracksIndex[i - 1])
+                if (i > 0 && span.startLine() <= flexibleSizedTracksIndex[i - 1])
                     continue;
 
                 flexFraction = std::max(flexFraction, findFlexFactorUnitSize(tracks, span, direction, maxContentForChild(*gridItem, direction, sizingData.columnTracks)));
@@ -868,7 +868,7 @@
 
 void RenderGrid::resolveContentBasedTrackSizingFunctionsForNonSpanningItems(GridTrackSizingDirection direction, const GridSpan& span, RenderBox& gridItem, GridTrack& track, Vector<GridTrack>& columnTracks)
 {
-    unsigned trackPosition = span.resolvedInitialPosition();
+    unsigned trackPosition = span.startLine();
     GridTrackSize trackSize = gridTrackSize(direction, trackPosition);
 
     if (trackSize.hasMinContentMinTrackBreadth())
@@ -1142,7 +1142,7 @@
 void RenderGrid::insertItemIntoGrid(RenderBox& child, const GridArea& area)
 {
     ASSERT(area.rows.isTranslatedDefinite() && area.columns.isTranslatedDefinite());
-    ensureGridSize(area.rows.resolvedFinalPosition(), area.columns.resolvedFinalPosition());
+    ensureGridSize(area.rows.endLine(), area.columns.endLine());
 
     for (auto row : area.rows) {
         for (auto column : area.columns)
@@ -1214,8 +1214,8 @@
 
         GridSpan rowPositions = GridPositionsResolver::resolveGridPositionsFromStyle(style(), *child, ForRows);
         if (!rowPositions.isIndefinite()) {
-            m_smallestRowStart = std::min(m_smallestRowStart, rowPositions.untranslatedResolvedInitialPosition());
-            maximumRowIndex = std::max<int>(maximumRowIndex, rowPositions.untranslatedResolvedFinalPosition());
+            m_smallestRowStart = std::min(m_smallestRowStart, rowPositions.untranslatedStartLine());
+            maximumRowIndex = std::max<int>(maximumRowIndex, rowPositions.untranslatedEndLine());
         } else {
             // Grow the grid for items with a definite row span, getting the largest such span.
             unsigned spanSize = GridPositionsResolver::spanSizeForAutoPlacedItem(style(), *child, ForRows);
@@ -1224,8 +1224,8 @@
 
         GridSpan columnPositions = GridPositionsResolver::resolveGridPositionsFromStyle(style(), *child, ForColumns);
         if (!columnPositions.isIndefinite()) {
-            m_smallestColumnStart = std::min(m_smallestColumnStart, columnPositions.untranslatedResolvedInitialPosition());
-            maximumColumnIndex = std::max<int>(maximumColumnIndex, columnPositions.untranslatedResolvedFinalPosition());
+            m_smallestColumnStart = std::min(m_smallestColumnStart, columnPositions.untranslatedStartLine());
+            maximumColumnIndex = std::max<int>(maximumColumnIndex, columnPositions.untranslatedEndLine());
         } else {
             // Grow the grid for items with a definite column span, getting the largest such span.
             unsigned spanSize = GridPositionsResolver::spanSizeForAutoPlacedItem(style(), *child, ForColumns);
@@ -1264,9 +1264,9 @@
         ASSERT(majorAxisPositions.isTranslatedDefinite());
         ASSERT(cachedGridSpan(*autoGridItem, autoPlacementMinorAxisDirection()).isIndefinite());
         unsigned minorAxisSpanSize = GridPositionsResolver::spanSizeForAutoPlacedItem(style(), *autoGridItem, autoPlacementMinorAxisDirection());
-        unsigned majorAxisInitialPosition = majorAxisPositions.resolvedInitialPosition();
+        unsigned majorAxisInitialPosition = majorAxisPositions.startLine();
 
-        GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions.resolvedInitialPosition(), isGridAutoFlowDense ? 0 : minorAxisCursors.get(majorAxisInitialPosition));
+        GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions.startLine(), isGridAutoFlowDense ? 0 : minorAxisCursors.get(majorAxisInitialPosition));
         std::unique_ptr<GridArea> emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions.integerSpan(), minorAxisSpanSize);
         if (!emptyGridArea)
             emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(*autoGridItem, autoPlacementMajorAxisDirection(), majorAxisPositions);
@@ -1275,7 +1275,7 @@
         insertItemIntoGrid(*autoGridItem, *emptyGridArea);
 
         if (!isGridAutoFlowDense)
-            minorAxisCursors.set(majorAxisInitialPosition, isForColumns ? emptyGridArea->rows.resolvedInitialPosition() : emptyGridArea->columns.resolvedInitialPosition());
+            minorAxisCursors.set(majorAxisInitialPosition, isForColumns ? emptyGridArea->rows.startLine() : emptyGridArea->columns.startLine());
     }
 }
 
@@ -1307,11 +1307,11 @@
     GridSpan minorAxisPositions = cachedGridSpan(gridItem, autoPlacementMinorAxisDirection());
     if (minorAxisPositions.isTranslatedDefinite()) {
         // Move to the next track in major axis if initial position in minor axis is before auto-placement cursor.
-        if (minorAxisPositions.resolvedInitialPosition() < minorAxisAutoPlacementCursor)
+        if (minorAxisPositions.startLine() < minorAxisAutoPlacementCursor)
             majorAxisAutoPlacementCursor++;
 
         if (majorAxisAutoPlacementCursor < endOfMajorAxis) {
-            GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisPositions.resolvedInitialPosition(), majorAxisAutoPlacementCursor);
+            GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisPositions.startLine(), majorAxisAutoPlacementCursor);
             emptyGridArea = iterator.nextEmptyGridArea(minorAxisPositions.integerSpan(), majorAxisSpanSize);
         }
 
@@ -1326,7 +1326,7 @@
 
             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()).
-                unsigned minorAxisFinalPositionIndex = autoPlacementMinorAxisDirection() == ForColumns ? emptyGridArea->columns.resolvedFinalPosition() : emptyGridArea->rows.resolvedFinalPosition();
+                unsigned minorAxisFinalPositionIndex = autoPlacementMinorAxisDirection() == ForColumns ? emptyGridArea->columns.endLine() : emptyGridArea->rows.endLine();
                 const unsigned endOfMinorAxis = autoPlacementMinorAxisDirection() == ForColumns ? gridColumnCount() : gridRowCount();
                 if (minorAxisFinalPositionIndex <= endOfMinorAxis)
                     break;
@@ -1346,8 +1346,8 @@
 
     m_gridItemArea.set(&gridItem, *emptyGridArea);
     insertItemIntoGrid(gridItem, *emptyGridArea);
-    autoPlacementCursor.first = emptyGridArea->rows.resolvedInitialPosition();
-    autoPlacementCursor.second = emptyGridArea->columns.resolvedInitialPosition();
+    autoPlacementCursor.first = emptyGridArea->rows.startLine();
+    autoPlacementCursor.second = emptyGridArea->columns.startLine();
 }
 
 GridTrackSizingDirection RenderGrid::autoPlacementMajorAxisDirection() const
@@ -1495,8 +1495,8 @@
 
     // For positioned items we cannot use GridSpan::translate() because we could end up with negative values, as the positioned items do not create implicit tracks per spec.
     int smallestStart = std::abs(isRowAxis ? m_smallestColumnStart : m_smallestRowStart);
-    int resolvedInitialPosition = positions.untranslatedResolvedInitialPosition() + smallestStart;
-    int resolvedFinalPosition = positions.untranslatedResolvedFinalPosition() + smallestStart;
+    int startLine = positions.untranslatedStartLine() + smallestStart;
+    int endLine = positions.untranslatedEndLine() + smallestStart;
 
     GridPosition startPosition = isRowAxis ? child.style().gridItemColumnStart() : child.style().gridItemRowStart();
     GridPosition endPosition = isRowAxis ? child.style().gridItemColumnEnd() : child.style().gridItemRowEnd();
@@ -1505,15 +1505,15 @@
 
     bool startIsAuto = startPosition.isAuto()
         || (startPosition.isNamedGridArea() && GridPositionsResolver::isNonExistentNamedLineOrArea(startPosition.namedGridLine(), style(), (direction == ForColumns) ? ColumnStartSide : RowStartSide))
-        || (resolvedInitialPosition < firstExplicitLine)
-        || (resolvedInitialPosition > lastExplicitLine);
+        || (startLine < firstExplicitLine)
+        || (startLine > lastExplicitLine);
     bool endIsAuto = endPosition.isAuto()
         || (endPosition.isNamedGridArea() && GridPositionsResolver::isNonExistentNamedLineOrArea(endPosition.namedGridLine(), style(), (direction == ForColumns) ? ColumnEndSide : RowEndSide))
-        || (resolvedFinalPosition < firstExplicitLine)
-        || (resolvedFinalPosition > lastExplicitLine);
+        || (endLine < firstExplicitLine)
+        || (endLine > lastExplicitLine);
 
-    unsigned initialPosition = startIsAuto ? 0 : resolvedInitialPosition;
-    unsigned finalPosition = endIsAuto ? lastExplicitLine : resolvedFinalPosition;
+    unsigned initialPosition = startIsAuto ? 0 : startLine;
+    unsigned finalPosition = endIsAuto ? lastExplicitLine : endLine;
 
     LayoutUnit start = startIsAuto ? LayoutUnit() : isRowAxis ?  m_columnPositions[initialPosition] : m_rowPositions[initialPosition];
     LayoutUnit end = endIsAuto ? (isRowAxis ? logicalWidth() : logicalHeight()) : (isRowAxis ?  m_columnPositions[finalPosition] : m_rowPositions[finalPosition]);
@@ -1574,11 +1574,11 @@
     const auto& span = cachedGridSpan(child, direction);
     const auto& linePositions = (direction == ForColumns) ? m_columnPositions : m_rowPositions;
 
-    LayoutUnit initialTrackPosition = linePositions[span.resolvedInitialPosition()];
-    LayoutUnit finalTrackPosition = linePositions[span.resolvedFinalPosition() - 1];
+    LayoutUnit initialTrackPosition = linePositions[span.startLine()];
+    LayoutUnit finalTrackPosition = linePositions[span.endLine() - 1];
 
     // Track Positions vector stores the 'start' grid line of each track, so we have to add last track's baseSize.
-    return finalTrackPosition - initialTrackPosition + tracks[span.resolvedFinalPosition() - 1].baseSize();
+    return finalTrackPosition - initialTrackPosition + tracks[span.endLine() - 1].baseSize();
 }
 
 void RenderGrid::populateGridPositions(GridSizingData& sizingData)
@@ -1857,7 +1857,7 @@
 LayoutUnit RenderGrid::columnAxisOffsetForChild(const RenderBox& child) const
 {
     const GridSpan& rowsSpan = cachedGridSpan(child, ForRows);
-    unsigned childStartLine = rowsSpan.resolvedInitialPosition();
+    unsigned childStartLine = rowsSpan.startLine();
     LayoutUnit startOfRow = m_rowPositions[childStartLine];
     LayoutUnit startPosition = startOfRow + marginBeforeForChild(child);
     if (hasAutoMarginsInColumnAxis(child))
@@ -1868,7 +1868,7 @@
         return startPosition;
     case GridAxisEnd:
     case GridAxisCenter: {
-        unsigned childEndLine = rowsSpan.resolvedFinalPosition();
+        unsigned childEndLine = rowsSpan.endLine();
         LayoutUnit endOfRow = m_rowPositions[childEndLine];
         // m_rowPositions include gutters so we need to substract them to get the actual end position for a given
         // row (this does not have to be done for the last track as there are no more m_rowPositions after it)
@@ -1891,7 +1891,7 @@
 LayoutUnit RenderGrid::rowAxisOffsetForChild(const RenderBox& child) const
 {
     const GridSpan& columnsSpan = cachedGridSpan(child, ForColumns);
-    unsigned childStartLine = columnsSpan.resolvedInitialPosition();
+    unsigned childStartLine = columnsSpan.startLine();
     LayoutUnit startOfColumn = m_columnPositions[childStartLine];
     LayoutUnit startPosition = startOfColumn + marginStartForChild(child);
     if (hasAutoMarginsInRowAxis(child))
@@ -1902,7 +1902,7 @@
         return startPosition;
     case GridAxisEnd:
     case GridAxisCenter: {
-        unsigned childEndLine = columnsSpan.resolvedFinalPosition();
+        unsigned childEndLine = columnsSpan.endLine();
         LayoutUnit endOfColumn = m_columnPositions[childEndLine];
         // m_columnPositions include gutters so we need to substract them to get the actual end position for a given
         // column (this does not have to be done for the last track as there are no more m_columnPositions after it)
diff --git a/Source/WebCore/rendering/style/GridArea.h b/Source/WebCore/rendering/style/GridArea.h
index 898063e..c2ef253 100644
--- a/Source/WebCore/rendering/style/GridArea.h
+++ b/Source/WebCore/rendering/style/GridArea.h
@@ -43,20 +43,20 @@
 // Recommended maximum size for both explicit and implicit grids.
 const int kGridMaxTracks = 1000000;
 
-// A span in a single direction (either rows or columns). Note that |resolvedInitialPosition|
-// and |resolvedFinalPosition| are grid lines' indexes.
-// Iterating over the span shouldn't include |resolvedFinalPosition| to be correct.
+// A span in a single direction (either rows or columns). Note that |startLine|
+// and |endLine| are grid lines' indexes.
+// Despite line numbers in the spec start in "1", the indexes here start in "0".
 class GridSpan {
 public:
 
-    static GridSpan untranslatedDefiniteGridSpan(int resolvedInitialPosition, int resolvedFinalPosition)
+    static GridSpan untranslatedDefiniteGridSpan(int startLine, int endLine)
     {
-        return GridSpan(resolvedInitialPosition, resolvedFinalPosition, UntranslatedDefinite);
+        return GridSpan(startLine, endLine, UntranslatedDefinite);
     }
 
-    static GridSpan translatedDefiniteGridSpan(unsigned resolvedInitialPosition, unsigned resolvedFinalPosition)
+    static GridSpan translatedDefiniteGridSpan(unsigned startLine, unsigned endLine)
     {
-        return GridSpan(resolvedInitialPosition, resolvedFinalPosition, TranslatedDefinite);
+        return GridSpan(startLine, endLine, TranslatedDefinite);
     }
 
     static GridSpan indefiniteGridSpan()
@@ -66,39 +66,39 @@
 
     bool operator==(const GridSpan& o) const
     {
-        return m_type == o.m_type && m_resolvedInitialPosition == o.m_resolvedInitialPosition && m_resolvedFinalPosition == o.m_resolvedFinalPosition;
+        return m_type == o.m_type && m_startLine == o.m_startLine && m_endLine == o.m_endLine;
     }
 
     unsigned integerSpan() const
     {
         ASSERT(isTranslatedDefinite());
-        return m_resolvedFinalPosition - m_resolvedInitialPosition;
+        return m_endLine - m_startLine;
     }
 
-    int untranslatedResolvedInitialPosition() const
+    int untranslatedStartLine() const
     {
         ASSERT(m_type == UntranslatedDefinite);
-        return m_resolvedInitialPosition;
+        return m_startLine;
     }
 
-    int untranslatedResolvedFinalPosition() const
+    int untranslatedEndLine() const
     {
         ASSERT(m_type == UntranslatedDefinite);
-        return m_resolvedFinalPosition;
+        return m_endLine;
     }
 
-    unsigned resolvedInitialPosition() const
+    unsigned startLine() const
     {
         ASSERT(isTranslatedDefinite());
-        ASSERT(m_resolvedFinalPosition >= 0);
-        return m_resolvedInitialPosition;
+        ASSERT(m_endLine >= 0);
+        return m_startLine;
     }
 
-    unsigned resolvedFinalPosition() const
+    unsigned endLine() const
     {
         ASSERT(isTranslatedDefinite());
-        ASSERT(m_resolvedFinalPosition > 0);
-        return m_resolvedFinalPosition;
+        ASSERT(m_endLine > 0);
+        return m_endLine;
     }
 
     struct GridSpanIterator {
@@ -116,13 +116,13 @@
     GridSpanIterator begin() const
     {
         ASSERT(isTranslatedDefinite());
-        return m_resolvedInitialPosition;
+        return m_startLine;
     }
 
     GridSpanIterator end() const
     {
         ASSERT(isTranslatedDefinite());
-        return m_resolvedFinalPosition;
+        return m_endLine;
     }
 
     bool isTranslatedDefinite() const
@@ -140,34 +140,34 @@
         ASSERT(m_type == UntranslatedDefinite);
 
         m_type = TranslatedDefinite;
-        m_resolvedInitialPosition += offset;
-        m_resolvedFinalPosition += offset;
+        m_startLine += offset;
+        m_endLine += offset;
 
-        ASSERT(m_resolvedInitialPosition >= 0);
-        ASSERT(m_resolvedFinalPosition > 0);
+        ASSERT(m_startLine >= 0);
+        ASSERT(m_endLine > 0);
     }
 
 private:
 
     enum GridSpanType {UntranslatedDefinite, TranslatedDefinite, Indefinite};
 
-    GridSpan(int resolvedInitialPosition, int resolvedFinalPosition, GridSpanType type)
+    GridSpan(int startLine, int endLine, GridSpanType type)
         : m_type(type)
     {
 #if ENABLE(ASSERT)
-        ASSERT(resolvedInitialPosition < resolvedFinalPosition);
+        ASSERT(startLine < endLine);
         if (type == TranslatedDefinite) {
-            ASSERT(resolvedInitialPosition >= 0);
-            ASSERT(resolvedFinalPosition > 0);
+            ASSERT(startLine >= 0);
+            ASSERT(endLine > 0);
         }
 #endif
 
-        m_resolvedInitialPosition = std::max(-kGridMaxTracks, std::min(resolvedInitialPosition, kGridMaxTracks - 1));
-        m_resolvedFinalPosition = std::max(-kGridMaxTracks + 1, std::min(resolvedFinalPosition, kGridMaxTracks));
+        m_startLine = std::max(-kGridMaxTracks, std::min(startLine, kGridMaxTracks - 1));
+        m_endLine = std::max(-kGridMaxTracks + 1, std::min(endLine, kGridMaxTracks));
     }
 
-    int m_resolvedInitialPosition;
-    int m_resolvedFinalPosition;
+    int m_startLine;
+    int m_endLine;
     GridSpanType m_type;
 
 
diff --git a/Source/WebCore/rendering/style/GridPositionsResolver.cpp b/Source/WebCore/rendering/style/GridPositionsResolver.cpp
index 90c46ea..76eaeec 100644
--- a/Source/WebCore/rendering/style/GridPositionsResolver.cpp
+++ b/Source/WebCore/rendering/style/GridPositionsResolver.cpp
@@ -169,22 +169,22 @@
     return lookBackForNamedGridLine(lastLine, std::abs(position.integerPosition()), gridLines, lastLine);
 }
 
-static GridSpan definiteGridSpanWithNamedLineSpanAgainstOpposite(int resolvedOppositePosition, const GridPosition& position, GridPositionSide side, const Vector<unsigned>* gridLines, unsigned lastLine)
+static GridSpan definiteGridSpanWithNamedLineSpanAgainstOpposite(int oppositeLine, const GridPosition& position, GridPositionSide side, const Vector<unsigned>* gridLines, unsigned lastLine)
 {
     int start, end;
 
     if (side == RowStartSide || side == ColumnStartSide) {
-        start = lookBackForNamedGridLine(resolvedOppositePosition - 1, position.spanPosition(), gridLines, lastLine);
-        end = resolvedOppositePosition;
+        start = lookBackForNamedGridLine(oppositeLine - 1, position.spanPosition(), gridLines, lastLine);
+        end = oppositeLine;
     } else {
-        start = resolvedOppositePosition;
-        end = lookAheadForNamedGridLine(resolvedOppositePosition + 1, position.spanPosition(), gridLines, lastLine);
+        start = oppositeLine;
+        end = lookAheadForNamedGridLine(oppositeLine + 1, position.spanPosition(), gridLines, lastLine);
     }
 
     return GridSpan::untranslatedDefiniteGridSpan(start, end);
 }
 
-static GridSpan resolveNamedGridLinePositionAgainstOppositePosition(const RenderStyle& gridContainerStyle, int resolvedOppositePosition, const GridPosition& position, GridPositionSide side)
+static GridSpan resolveNamedGridLinePositionAgainstOppositePosition(const RenderStyle& gridContainerStyle, int oppositeLine, const GridPosition& position, GridPositionSide side)
 {
     ASSERT(position.isSpan());
     ASSERT(!position.namedGridLine().isNull());
@@ -196,15 +196,15 @@
     const Vector<unsigned>* gridLines = iterator == gridLinesNames.end() ? nullptr : &iterator->value;
     unsigned lastLine = explicitGridSizeForSide(gridContainerStyle, side);
 
-    return definiteGridSpanWithNamedLineSpanAgainstOpposite(resolvedOppositePosition, position, side, gridLines, lastLine);
+    return definiteGridSpanWithNamedLineSpanAgainstOpposite(oppositeLine, position, side, gridLines, lastLine);
 }
 
-static GridSpan resolveGridPositionAgainstOppositePosition(const RenderStyle& gridContainerStyle, int resolvedOppositePosition, const GridPosition& position, GridPositionSide side)
+static GridSpan resolveGridPositionAgainstOppositePosition(const RenderStyle& gridContainerStyle, int oppositeLine, const GridPosition& position, GridPositionSide side)
 {
     if (position.isAuto()) {
         if (isStartSide(side))
-            return GridSpan::untranslatedDefiniteGridSpan(resolvedOppositePosition - 1, resolvedOppositePosition);
-        return GridSpan::untranslatedDefiniteGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
+            return GridSpan::untranslatedDefiniteGridSpan(oppositeLine - 1, oppositeLine);
+        return GridSpan::untranslatedDefiniteGridSpan(oppositeLine, oppositeLine + 1);
     }
 
     ASSERT(position.isSpan());
@@ -212,16 +212,16 @@
 
     if (!position.namedGridLine().isNull()) {
         // span 2 'c' -> we need to find the appropriate grid line before / after our opposite position.
-        return resolveNamedGridLinePositionAgainstOppositePosition(gridContainerStyle, resolvedOppositePosition, position, side);
+        return resolveNamedGridLinePositionAgainstOppositePosition(gridContainerStyle, oppositeLine, position, side);
     }
 
     // 'span 1' is contained inside a single grid track regardless of the direction.
     // That's why the CSS span value is one more than the offset we apply.
     unsigned positionOffset = position.spanPosition();
     if (isStartSide(side))
-        return GridSpan::untranslatedDefiniteGridSpan(resolvedOppositePosition - positionOffset, resolvedOppositePosition);
+        return GridSpan::untranslatedDefiniteGridSpan(oppositeLine - positionOffset, oppositeLine);
 
-    return GridSpan::untranslatedDefiniteGridSpan(resolvedOppositePosition, resolvedOppositePosition + positionOffset);
+    return GridSpan::untranslatedDefiniteGridSpan(oppositeLine, oppositeLine + positionOffset);
 }
 
 unsigned GridPositionsResolver::spanSizeForAutoPlacedItem(const RenderStyle& gridContainerStyle, const RenderBox& gridItem, GridTrackSizingDirection direction)
@@ -308,25 +308,25 @@
 
     if (initialPosition.shouldBeResolvedAgainstOppositePosition()) {
         // Infer the position from the final position ('auto / 1' or 'span 2 / 3' case).
-        auto finalResolvedPosition = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
-        return resolveGridPositionAgainstOppositePosition(gridContainerStyle, finalResolvedPosition, initialPosition, initialSide);
+        auto endLine = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
+        return resolveGridPositionAgainstOppositePosition(gridContainerStyle, endLine, initialPosition, initialSide);
     }
 
     if (finalPosition.shouldBeResolvedAgainstOppositePosition()) {
         // Infer our position from the initial position ('1 / auto' or '3 / span 2' case).
-        auto initialResolvedPosition = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
-        return resolveGridPositionAgainstOppositePosition(gridContainerStyle, initialResolvedPosition, finalPosition, finalSide);
+        auto startLine = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
+        return resolveGridPositionAgainstOppositePosition(gridContainerStyle, startLine, finalPosition, finalSide);
     }
 
-    int resolvedInitialPosition = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
-    int resolvedFinalPosition = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
+    int startLine = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
+    int endLine = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
 
-    if (resolvedInitialPosition > resolvedFinalPosition)
-        std::swap(resolvedInitialPosition, resolvedFinalPosition);
-    else if (resolvedInitialPosition == resolvedFinalPosition)
-        resolvedFinalPosition = resolvedInitialPosition + 1;
+    if (startLine > endLine)
+        std::swap(startLine, endLine);
+    else if (startLine == endLine)
+        endLine = startLine + 1;
 
-    return GridSpan::untranslatedDefiniteGridSpan(resolvedInitialPosition, std::max(resolvedInitialPosition, resolvedFinalPosition));
+    return GridSpan::untranslatedDefiniteGridSpan(startLine, std::max(startLine, endLine));
 }
 
 } // namespace WebCore