Revert commit# 415577 "Add grid/flex layout support for <fieldset>"

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

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1403 matching lines @@
 
 void LayoutBlockFlow::layoutBlockChildren(bool relayoutChildren,
                                           SubtreeLayoutScope& layoutScope,
                                           LayoutUnit beforeEdge,
                                           LayoutUnit afterEdge) {
   dirtyForLayoutFromPercentageHeightDescendants(layoutScope);
 
   BlockChildrenLayoutInfo layoutInfo(this, beforeEdge, afterEdge);
   MarginInfo& marginInfo = layoutInfo.marginInfo();
 
+  // Fieldsets need to find their legend and position it inside the border of
+  // the object.
+  // The legend then gets skipped during normal layout. The same is true for
+  // ruby text.
+  // It doesn't get included in the normal layout process but is instead skipped
   LayoutObject* childToExclude =
       layoutSpecialExcludedChild(relayoutChildren, layoutScope);
 
   // TODO(foolip): Speculative CHECKs to crash if any non-LayoutBox
   // children ever appear, the childrenInline() check at the call site
   // should make this impossible. crbug.com/632848
   LayoutObject* firstChild = this->firstChild();
   CHECK(!firstChild || firstChild->isBox());
   LayoutBox* next = toLayoutBox(firstChild);
   LayoutBox* lastNormalFlowChild = nullptr;
 
   while (next) {
     LayoutBox* child = next;
     LayoutObject* nextSibling = child->nextSibling();
     CHECK(!nextSibling || nextSibling->isBox());
     next = toLayoutBox(nextSibling);
 
     child->setMayNeedPaintInvalidation();
 
     if (childToExclude == child)
       continue;  // Skip this child, since it will be positioned by the
-                 // specialized subclass (ruby runs).
+                 // specialized subclass (fieldsets and ruby runs).
 
     updateBlockChildDirtyBitsBeforeLayout(relayoutChildren, *child);
 
     if (child->isOutOfFlowPositioned()) {
       child->containingBlock()->insertPositionedObject(child);
       adjustPositionedBlock(*child, layoutInfo);
       continue;
     }
     if (child->isFloating()) {
       insertFloatingObject(*child);
@@ skipping 1501 matching lines @@
       return;
     }
   }
 
   // Skip the LayoutBlock override, since that one deals with anonymous child
   // insertion in a way that isn't sufficient for us, and can only cause trouble
   // at this point.
   LayoutBox::addChild(newChild, beforeChild);
 
   if (madeBoxesNonInline && parent() && isAnonymousBlock() &&
-      parent()->isLayoutBlock() && !parent()->createsAnonymousWrapper()) {
+      parent()->isLayoutBlock()) {
     toLayoutBlock(parent())->removeLeftoverAnonymousBlock(this);
     // |this| may be dead now.
   }
 }
 
 static bool isMergeableAnonymousBlock(const LayoutBlockFlow* block) {
   return block->isAnonymousBlock() && !block->continuation() &&
          !block->beingDestroyed() && !block->isRubyRun() &&
          !block->isRubyBase();
 }
@@ skipping 1263 matching lines @@
 
   if (type == NoFlowThread || multiColumnFlowThread())
     return;
 
   // Ruby elements manage child insertion in a special way, and would mess up
   // insertion of the flow thread. The flow thread needs to be a direct child of
   // the multicol block (|this|).
   if (isRuby())
     return;
 
+  // Fieldsets look for a legend special child (layoutSpecialExcludedChild()).
+  // We currently only support one special child per layout object, and the
+  // flow thread would make for a second one.
+  if (isFieldset())
+    return;
+
   // Form controls are replaced content, and are therefore not supposed to
   // support multicol.
   if (isFileUploadControl() || isTextControl() || isListBox())
     return;
 
   LayoutMultiColumnFlowThread* flowThread = createMultiColumnFlowThread(type);
   addChild(flowThread);
   m_paginationStateChanged = true;
 
   // Check that addChild() put the flow thread as a direct child, and didn't do
@@ skipping 307 matching lines @@
   return LayoutBlock::invalidatePaintIfNeeded(paintInvalidationState);
 }
 
 void LayoutBlockFlow::invalidateDisplayItemClients(
     PaintInvalidationReason invalidationReason) const {
   BlockFlowPaintInvalidator(*this).invalidateDisplayItemClients(
       invalidationReason);
 }
 
 }  // namespace blink