[css-grid] Fix behavior of positioned items without specific dimensions

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 1245 matching lines @@
     LayoutUnit column_breadth = LayoutUnit();
     OffsetAndBreadthForPositionedChild(*child, kForColumns, column_offset,
                                        column_breadth);
     LayoutUnit row_offset = LayoutUnit();
     LayoutUnit row_breadth = LayoutUnit();
     OffsetAndBreadthForPositionedChild(*child, kForRows, row_offset,
                                        row_breadth);
 
     child->SetOverrideContainingBlockContentLogicalWidth(column_breadth);
     child->SetOverrideContainingBlockContentLogicalHeight(row_breadth);
-    child->SetExtraInlineOffset(column_offset);
-    child->SetExtraBlockOffset(row_offset);
 
-    if (child->Parent() == this) {
-      PaintLayer* child_layer = child->Layer();
-      child_layer->SetStaticInlinePosition(BorderStart() + column_offset);
-      child_layer->SetStaticBlockPosition(BorderBefore() + row_offset);
-    }
+    child->SetX(LayoutUnit());
+    child->SetY(LayoutUnit());

[svillar, 2017/05/08 11:18:10]

Why do we need this?

[Manuel Rego, 2017/05/08 13:29:44]

Actually this is a leftover from a previous version of the patch.
We don't need this.

+
+    // Mark for layout as we're resetting the position before and we relay in
+    // generic layout logic for positioned items in order to get the offsets
+    // properly resolved.
+    SubtreeLayoutScope layout_scope(*child);
+    layout_scope.SetChildNeedsLayout(child);

[svillar, 2017/05/08 11:18:10]

Why are you using a SubtreeLayoutScope here? Wouldn't it be enough just to mark
the child as NeedsLayout ?

[Manuel Rego, 2017/05/08 13:29:44]

I just copied it from LayoutBlock::LayoutPositionedObject(),
but it's true I can simply use SetNeedsLayout().
Changed it in the last version.

 
     LayoutPositionedObject(child, relayout_children, info);
+
+    child->SetLogicalLocation(LayoutPoint(child->LogicalLeft() + column_offset,
+                                          child->LogicalTop() + row_offset));
   }
 }
 
 void LayoutGrid::OffsetAndBreadthForPositionedChild(
     const LayoutBox& child,
     GridTrackSizingDirection direction,
     LayoutUnit& offset,
     LayoutUnit& breadth) {
   DCHECK(!IsOrthogonalChild(child));
   bool is_for_columns = direction == kForColumns;
@@ skipping 71 matching lines @@
       DCHECK(!grid_.NeedsItemsPlacement());
       end -= GuttersSize(grid_, direction, end_line - 1, 2,
                          available_size_for_gutters);
       end -= is_for_columns ? offset_between_columns_ : offset_between_rows_;
     }
   }
 
   breadth = std::max(end - start, LayoutUnit());
   offset = start;
 
-  if (is_for_columns && !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
+  if (is_for_columns && !StyleRef().IsLeftToRightDirection()) {
+    // We always want to calculate the static position from the left
     // (even if we're in RTL).
     if (end_is_auto) {
       offset = LayoutUnit();
     } else {
       offset = TranslateRTLCoordinate(column_positions_[end_line]) -
                BorderLogicalLeft();
 
       if (end_line > 0 && end_line < last_line) {
         DCHECK(!grid_.NeedsItemsPlacement());
         offset += GuttersSize(grid_, direction, end_line - 1, 2,
@@ skipping 1022 matching lines @@
   if (direction == kForRows)
     return grid.NumTracks(kForRows);
 
   return grid.NumTracks(kForRows)
              ? grid.NumTracks(kForColumns)
              : GridPositionsResolver::ExplicitGridColumnCount(
                    StyleRef(), grid.AutoRepeatTracks(kForColumns));
 }
 
 }  // namespace blink