[css-grid] Refactor code to manage positioned items

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 1678 matching lines @@
 
     bool startIsAuto = startPosition.isAuto()
         || (startPosition.isNamedGridArea() && !NamedLineCollection::isValidNamedLineOrArea(startPosition.namedGridLine(), styleRef(), GridPositionsResolver::initialPositionSide(direction)))
         || (startLine < firstExplicitLine)
         || (startLine > lastExplicitLine);
     bool endIsAuto = endPosition.isAuto()
         || (endPosition.isNamedGridArea() && !NamedLineCollection::isValidNamedLineOrArea(endPosition.namedGridLine(), styleRef(), GridPositionsResolver::finalPositionSide(direction)))
         || (endLine < firstExplicitLine)
         || (endLine > lastExplicitLine);
 
-    // We're normalizing the positions to avoid issues with RTL (as they're stored in the same order than LTR but adding an offset).
     LayoutUnit start;
     if (!startIsAuto) {
-        if (isForColumns)
-            start = m_columnPositions[startLine] - m_columnPositions[0] + paddingStart();
-        else
-            start = m_rowPositions[startLine] - m_rowPositions[0] + paddingBefore();
+        if (isForColumns) {
+            if (styleRef().isLeftToRightDirection())
+                start = m_columnPositions[startLine] - borderLogicalLeft();
+            else
+                start = logicalWidth() - translateRTLCoordinate(m_columnPositions[startLine]) - borderLogicalRight();
+        } else {
+            start = m_rowPositions[startLine] - borderBefore();
+        }
     }
 
     LayoutUnit end = isForColumns ? clientLogicalWidth() : clientLogicalHeight();
     if (!endIsAuto) {
-        if (isForColumns)
-            end = m_columnPositions[endLine] - m_columnPositions[0] + paddingStart();
-        else
-            end = m_rowPositions[endLine] - m_rowPositions[0] + paddingBefore();
+        if (isForColumns) {
+            if (styleRef().isLeftToRightDirection())
+                end = m_columnPositions[endLine] - borderLogicalLeft();
+            else
+                end = logicalWidth() - translateRTLCoordinate(m_columnPositions[endLine]) - borderLogicalRight();
+        } else {
+            end = m_rowPositions[endLine] - borderBefore();
+        }
 
         // These vectors store line positions including gaps, but we shouldn't consider them for the edges of the grid.
         if (endLine > firstExplicitLine && endLine < lastExplicitLine) {
             end -= guttersSize(direction, 2);
             end -= isForColumns ? m_offsetBetweenColumns : m_offsetBetweenRows;
         }
     }
 
-    LayoutUnit alignmentOffset = isForColumns ? m_columnPositions[0] - borderAndPaddingLogicalLeft() : m_rowPositions[0] - borderAndPaddingBefore();
-    if (isForColumns && !styleRef().isLeftToRightDirection())
-        alignmentOffset = contentLogicalWidth() - (m_columnPositions[m_columnPositions.size() - 1] - borderAndPaddingLogicalLeft());
-
-    if (!startIsAuto)
-        start += alignmentOffset;
-    if (!endIsAuto)
-        end += alignmentOffset;
-
     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 {
             offset = translateRTLCoordinate(m_columnPositions[endLine]) - borderLogicalLeft();
@@ skipping 496 matching lines @@
 
     return LayoutPoint(rowAxisOffset, columnAxisOffsetForChild(child, sizingData));
 }
 
 void LayoutGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
 {
     GridPainter(*this).paintChildren(paintInfo, paintOffset);
 }
 
 } // namespace blink