Add grid/flex layout support for <fieldset>

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

Index: third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp b/third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp
index 72f0687b7dc9b888388815d92075146b806f8bc4..e0ca01c7b3f54674b4cc0e5f320d819914eef387 100644
--- a/third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp
@@ -881,9 +881,14 @@ void LayoutFlexibleBox::layoutFlexItems(bool relayoutChildren, SubtreeLayoutScop
 
     PaintLayerScrollableArea::PreventRelayoutScope preventRelayoutScope(layoutScope);
 
+    // Fieldsets need to find their legend and position it inside the border of the object.
+    // The legend then gets skipped during normal layout.
+    // It doesn't get included in the normal layout process but is instead skipped.
+    LayoutObject* childToExclude = layoutSpecialExcludedChild(relayoutChildren, layoutScope);
+
     m_orderIterator.first();
     LayoutUnit crossAxisOffset = flowAwareBorderBefore() + flowAwarePaddingBefore();
-    while (computeNextFlexLine(orderedChildren, sumFlexBaseSize, totalFlexGrow, totalFlexShrink, totalWeightedFlexShrink, sumHypotheticalMainSize, relayoutChildren)) {
+    while (computeNextFlexLine(orderedChildren, sumFlexBaseSize, totalFlexGrow, totalFlexShrink, totalWeightedFlexShrink, sumHypotheticalMainSize, relayoutChildren, childToExclude)) {
         LayoutUnit containerMainInnerSize = mainAxisContentExtent(sumHypotheticalMainSize);
         // availableFreeSpace is the initial amount of free space in this flexbox.
         // remainingFreeSpace starts out at the same value but as we place and lay out
@@ -1200,7 +1205,7 @@ LayoutUnit LayoutFlexibleBox::adjustChildSizeForAspectRatioCrossAxisMinAndMax(co
     return childSize;
 }
 
-bool LayoutFlexibleBox::computeNextFlexLine(OrderedFlexItemList& orderedChildren, LayoutUnit& sumFlexBaseSize, double& totalFlexGrow, double& totalFlexShrink, double& totalWeightedFlexShrink, LayoutUnit& sumHypotheticalMainSize, bool relayoutChildren)
+bool LayoutFlexibleBox::computeNextFlexLine(OrderedFlexItemList& orderedChildren, LayoutUnit& sumFlexBaseSize, double& totalFlexGrow, double& totalFlexShrink, double& totalWeightedFlexShrink, LayoutUnit& sumHypotheticalMainSize, bool relayoutChildren, LayoutObject* childToExclude)
 {
     orderedChildren.clear();
     sumFlexBaseSize = LayoutUnit();
@@ -1215,6 +1220,10 @@ bool LayoutFlexibleBox::computeNextFlexLine(OrderedFlexItemList& orderedChildren
     bool lineHasInFlowItem = false;
 
     for (LayoutBox* child = m_orderIterator.currentChild(); child; child = m_orderIterator.next()) {
+
+        if (childToExclude == child)
+            continue; // Skip this child, since it will be positioned by the specialized subclass (fieldsets runs).
+
         if (child->isOutOfFlowPositioned()) {
             orderedChildren.append(FlexItem(child));
             continue;