Revert of Add grid/flex layout support for <fieldset>

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

Index: third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
index 91086f2643cf0d1d1f12a1ec13fe4ede9a028760..7148dcf83b9c7158784d0508ce8366d8c2697208 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -1143,6 +1143,9 @@
     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);
 
     LayoutBox* next = firstChildBox();
@@ -1155,7 +1158,7 @@
         child->setMayNeedPaintInvalidation();
 
         if (childToExclude == child)
-            continue; // Skip this child, since it will be positioned by the specialized subclass (ruby runs).
+            continue; // Skip this child, since it will be positioned by the specialized subclass (fieldsets and ruby runs).
 
         updateBlockChildDirtyBitsBeforeLayout(relayoutChildren, *child);
 
@@ -2394,7 +2397,7 @@
     // 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()) {
+    if (madeBoxesNonInline && parent() && isAnonymousBlock() && parent()->isLayoutBlock()) {
         toLayoutBlock(parent())->removeLeftoverAnonymousBlock(this);
         // |this| may be dead now.
     }
@@ -3520,6 +3523,11 @@
     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;