[css-grid] Improve intrinsic size computation with orthogonal flows

third_party/WebKit/Source/core/layout/GridTrackSizingAlgorithm.cpp

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/GridTrackSizingAlgorithm.h"
 
 #include "core/layout/Grid.h"
 #include "core/layout/LayoutGrid.h"
 #include "platform/LengthFunctions.h"
 
@@ skipping 285 matching lines @@
     // FIXME: It's unclear if we should return the intrinsic width or the
     // preferred width.
     // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
     LayoutUnit marginLogicalWidth =
         child.needsLayout() ? computeMarginLogicalSizeForChild(
                                   InlineDirection, layoutGrid(), child)
                             : child.marginLogicalWidth();
     return child.minPreferredLogicalWidth() + marginLogicalWidth;
   }
 
-  // All orthogonal flow boxes were already laid out during an early layout
-  // phase performed in FrameView::performLayout.
-  // It's true that grid track sizing was not completed at that time and it may
-  // afffect the final height of a grid item, but since it's forbidden to
-  // perform a layout during intrinsic width computation, we have to use that
-  // computed height for now.
-  if (direction() == ForColumns &&
-      m_algorithm.m_sizingOperation == IntrinsicSizeComputation) {
-    DCHECK(layoutGrid()->isOrthogonalChild(child));
-    return child.logicalHeight() + child.marginLogicalHeight();

[jfernandez, 2017/02/15 22:49:58]

Removing this code implies that we will mark the grid item for layout, if the
override size (its virtual containing block) has changed, and indeed perform
such layout in logicalHeightForChild in order to compute the column track's
width. 

For the record, I'm totally fine with it, since we were already doing it in the
FrameView, but just wanted to make it more explicit here to be considered by
other reviewers.

-  }
-
   if (updateOverrideContainingBlockContentSizeForChild(child,
                                                        childInlineDirection))
     child.setNeedsLayout(LayoutInvalidationReason::GridChanged);
   return logicalHeightForChild(child);
 }
 
 DISABLE_CFI_PERF
 LayoutUnit GridTrackSizingAlgorithmStrategy::maxContentForChild(
     LayoutBox& child) const {
   GridTrackSizingDirection childInlineDirection =
@@ skipping 11 matching lines @@
     // FIXME: It's unclear if we should return the intrinsic width or the
     // preferred width.
     // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
     LayoutUnit marginLogicalWidth =
         child.needsLayout() ? computeMarginLogicalSizeForChild(
                                   InlineDirection, layoutGrid(), child)
                             : child.marginLogicalWidth();
     return child.maxPreferredLogicalWidth() + marginLogicalWidth;
   }
 
-  if (direction() == ForColumns &&
-      m_algorithm.m_sizingOperation == IntrinsicSizeComputation) {
-    // All orthogonal flow boxes were already laid out during an early layout
-    // phase performed in FrameView::performLayout. It's true that grid track
-    // sizing was not completed at that time and it may afffect the final height
-    // of a grid item, but since it's forbidden to perform a layout during
-    // intrinsic width computation, we have to use that computed height for now.
-    DCHECK(layoutGrid()->isOrthogonalChild(child));
-    return child.logicalHeight() + child.marginLogicalHeight();

[jfernandez, 2017/02/15 22:49:58]

Ditto.

-  }
-
   if (updateOverrideContainingBlockContentSizeForChild(child,
                                                        childInlineDirection))
     child.setNeedsLayout(LayoutInvalidationReason::GridChanged);
   return logicalHeightForChild(child);
 }
 
 LayoutUnit GridTrackSizingAlgorithmStrategy::minSizeForChild(
     LayoutBox& child) const {
   GridTrackSizingDirection childInlineDirection =
       flowAwareDirectionForChild(layoutGrid(), child, ForColumns);
@@ skipping 1055 matching lines @@
   DCHECK(m_algorithm.isValidTransition());
   DCHECK(!m_algorithm.m_needsSetup);
 }
 
 GridTrackSizingAlgorithm::StateMachine::~StateMachine() {
   m_algorithm.advanceNextState();
   m_algorithm.m_needsSetup = true;
 }
 
 }  // namespace blink