[css-grid] Fix painting in RTL

third_party/WebKit/Source/core/layout/LayoutGrid.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
@@ skipping 1610 matching lines @@
 
     breadth = end - start;
     offset = start;
 
     if (isForColumns && !styleRef().isLeftToRightDirection() && !child.styleRef().hasStaticInlinePosition(child.isHorizontalWritingMode())) {
         // If the child doesn't have a static inline position (i.e. "left" and/or "right" aren't "auto",
         // we need to calculate the offset from the left (even if we're in RTL).
         if (endIsAuto) {
             offset = LayoutUnit();
         } else {
-            alignmentOffset = m_columnPositions[0] - borderAndPaddingStart();
-            LayoutUnit offsetFromLastLine = m_columnPositions[m_columnPositions.size() - 1] - m_columnPositions[endLine];
-            offset = paddingLeft() + alignmentOffset + offsetFromLastLine;
+            offset = translateRTLCoordinate(m_columnPositions[endLine]) - borderLeft();
 
             if (endLine > firstExplicitLine && endLine < lastExplicitLine) {
                 offset += guttersSize(direction, 2);
                 offset += isForColumns ? m_offsetBetweenColumns : m_offsetBetweenRows;
             }
         }
     }
 
     if (child.parent() == this && !startIsAuto) {
         // If column/row start is "auto" the static position has been already set in prepareChildForPositionedLayout().
@@ skipping 474 matching lines @@
             return {styleRef().isLeftToRightDirection() ? LayoutUnit() : availableFreeSpace, LayoutUnit()};
         return {LayoutUnit(), LayoutUnit()};
     case ContentPositionNormal:
         break;
     }
 
     ASSERT_NOT_REACHED();
     return {LayoutUnit(), LayoutUnit()};
 }
 
+LayoutUnit LayoutGrid::translateRTLCoordinate(LayoutUnit coordinate) const
+{
+    ASSERT(!styleRef().isLeftToRightDirection());
+
+    LayoutUnit alignmentOffset = m_columnPositions[0] - borderAndPaddingStart();
+    LayoutUnit rightGridEdgePosition = m_columnPositions[m_columnPositions.size() - 1];
+    return borderAndPaddingLogicalLeft() + rightGridEdgePosition + alignmentOffset - coordinate;
+}
+
 LayoutPoint LayoutGrid::findChildLogicalPosition(const LayoutBox& child, GridSizingData& sizingData) const
 {
     LayoutUnit rowAxisOffset = rowAxisOffsetForChild(child, sizingData);
     // We stored m_columnPosition'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()) {
-        LayoutUnit alignmentOffset =  m_columnPositions[0] - borderAndPaddingStart();
-        LayoutUnit rightGridEdgePosition = m_columnPositions[m_columnPositions.size() - 1] + alignmentOffset + borderAndPaddingLogicalLeft();
-        rowAxisOffset = rightGridEdgePosition - (rowAxisOffset + child.logicalWidth());
-    }
+    if (!style()->isLeftToRightDirection())
+        rowAxisOffset = translateRTLCoordinate(rowAxisOffset) - child.logicalWidth();
 
     return LayoutPoint(rowAxisOffset, columnAxisOffsetForChild(child, sizingData));
 }
 
 void LayoutGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
 {
     GridPainter(*this).paintChildren(paintInfo, paintOffset);
 }
 
 } // namespace blink