Percent height border-box content should get correct height in percent height cells

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 3167 matching lines @@
         containingBlockChild->containingBlockLogicalWidthForContent();
   } else if (hasOverrideContainingBlockLogicalHeight()) {
     availableHeight = overrideContainingBlockContentLogicalHeight();
   } else if (cb->isTableCell()) {
     if (!skippedAutoHeightContainingBlock) {
       // Table cells violate what the CSS spec says to do with heights.
       // Basically we don't care if the cell specified a height or not. We just
       // always make ourselves be a percentage of the cell's current content
       // height.
       if (!cb->hasOverrideLogicalContentHeight()) {
-        // Normally we would let the cell size intrinsically, but scrolling
-        // overflow has to be treated differently, since WinIE lets scrolled
-        // overflow regions shrink as needed.
-        // While we can't get all cases right, we can at least detect when the
-        // cell has a specified height or when the table has a specified height.
-        // In these cases we want to initially have no size and allow the
-        // flexing of the table or the cell to its specified height to cause us
-        // to grow to fill the space. This could end up being wrong in some
-        // cases, but it is preferable to the alternative (sizing intrinsically
-        // and making the row end up too big).
+        // https://drafts.csswg.org/css-tables-3/#row-layout:
+        // For the purpose of calculating [the minimum height of a row],
+        // descendants of table cells whose height depends on percentages
+        // of their parent cell's height are considered to have an auto
+        // height if they have overflow set to visible or hidden or if
+        // they are replaced elements, and a 0px height if they have not.
         LayoutTableCell* cell = toLayoutTableCell(cb);
+        bool treatAsReplaced = node() && node()->isElementNode() &&

[eae, 2016/12/12 19:55:19]

Could you add a comment (or update the one above) the mention the form
control/image element case?

+                               (toElement(node())->isFormControlElement() ||
+                                isHTMLImageElement(toElement(node())));
+        bool isReplaced = isAtomicInlineLevel() || treatAsReplaced;
         if (style()->overflowY() != OverflowVisible &&
-            style()->overflowY() != OverflowHidden &&
+            style()->overflowY() != OverflowHidden && !isReplaced &&
             (!cell->style()->logicalHeight().isAuto() ||
              !cell->table()->style()->logicalHeight().isAuto()))
           return LayoutUnit();
         return LayoutUnit(-1);
       }
       availableHeight = cb->overrideLogicalContentHeight();
     }
   } else {
     availableHeight = cb->availableLogicalHeightForPercentageComputation();
   }
 
   if (availableHeight == -1)
     return availableHeight;
 
   availableHeight -= rootMarginBorderPaddingHeight;
 
   if (isTable() && isOutOfFlowPositioned())
     availableHeight += cb->paddingLogicalHeight();
 
   LayoutUnit result = valueForLength(height, availableHeight);
-  bool includeBorderPadding =
+  // |overrideLogicalContentHeight| is the maximum height made available by the
+  // cell to its percent height children when we decide they can determine the
+  // height of the cell. If the percent height child is box-sizing:content-box
+  // then we must subtract the border and padding from the cell's
+  // |availableHeight| (given by |overrideLogicalContentHeight|) to arrive
+  // at the child's computed height.
+  bool subtractBorderAndPadding =
       isTable() || (cb->isTableCell() && !skippedAutoHeightContainingBlock &&
-                    cb->hasOverrideLogicalContentHeight());
-
-  if (includeBorderPadding) {
-    // FIXME: Table cells should default to box-sizing: border-box so we can
-    // avoid this hack.
-    // It is necessary to use the border-box to match WinIE's broken
-    // box model. This is essential for sizing inside
-    // table cells using percentage heights.
+                    cb->hasOverrideLogicalContentHeight() &&
+                    style()->boxSizing() == BoxSizingContentBox);
+  if (subtractBorderAndPadding) {
     result -= borderAndPaddingLogicalHeight();
     return std::max(LayoutUnit(), result);
   }
   return result;
 }
 
 LayoutUnit LayoutBox::computeReplacedLogicalWidth(
     ShouldComputePreferred shouldComputePreferred) const {
   return computeReplacedLogicalWidthRespectingMinMaxWidth(
       computeReplacedLogicalWidthUsing(MainOrPreferredSize,
@@ skipping 2411 matching lines @@
   LayoutRect rect = frameRect();
 
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink