[css-grid] Preemptively store intrinsic sizes during layout

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 262 matching lines @@
 
     // 1- First, the track sizing algorithm is used to resolve the sizes of the
     // grid columns.
     // At this point the logical width is always definite as the above call to
     // updateLogicalWidth() properly resolves intrinsic sizes. We cannot do the
     // same for heights though because many code paths inside
     // updateLogicalHeight() require a previous call to setLogicalHeight() to
     // resolve heights properly (like for positioned items for example).
     ComputeTrackSizesForDefiniteSize(kForColumns, available_space_for_columns);
 
+    // We take the chance to store the intrinsic sizes as they are just an
+    // intermediate result of the track sizing algorithm. Apart from eventually
+    // saving an algorithm execution (if {min|max}PreferredLogicalWidth() are
+    // called later), it fixes the use case of computing the preferred logical
+    // widths *after* the layout process. Although not very common, this happens
+    // in the Mac (content::RenderViewImpl::didUpdateLayout()) or under some
+    // circumstances when grids are also flex items (crbug.com/708159).
+    if (PreferredLogicalWidthsDirty()) {
+      LayoutUnit scrollbar_width = LayoutUnit(ScrollbarLogicalWidth());
+      min_preferred_logical_width_ =
+          track_sizing_algorithm_.MinContentSize() + scrollbar_width;
+      max_preferred_logical_width_ =
+          track_sizing_algorithm_.MaxContentSize() + scrollbar_width;
+      ClearPreferredLogicalWidthsDirty();
+    }
+
     // 2- Next, the track sizing algorithm resolves the sizes of the grid rows,
     // using the grid column sizes calculated in the previous step.
     if (CachedHasDefiniteLogicalHeight()) {
       ComputeTrackSizesForDefiniteSize(
           kForRows, AvailableLogicalHeight(kExcludeMarginBorderPadding));
     } else {
       ComputeTrackSizesForIndefiniteSize(track_sizing_algorithm_, kForRows,
                                          grid_, min_content_height_,
                                          max_content_height_);
     }
@@ skipping 2096 matching lines @@
   if (direction == kForRows)
     return grid.NumTracks(kForRows);
 
   return grid.NumTracks(kForRows)
              ? grid.NumTracks(kForColumns)
              : GridPositionsResolver::ExplicitGridColumnCount(
                    StyleRef(), grid.AutoRepeatTracks(kForColumns));
 }
 
 }  // namespace blink