Revert of Support margin-top for legend in fieldset.

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

Index: third_party/WebKit/Source/core/layout/LayoutFieldset.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutFieldset.cpp b/third_party/WebKit/Source/core/layout/LayoutFieldset.cpp
index 1527da1bdd632aaf0803296b2e45862baf241dfd..f21440a3e74f770c344fc45205a4277a3b8c0786 100644
--- a/third_party/WebKit/Source/core/layout/LayoutFieldset.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutFieldset.cpp
@@ -174,29 +174,27 @@ LayoutObject* LayoutFieldset::layoutSpecialExcludedChild(bool relayoutChildren,
     LayoutUnit legendLogicalTop;
     LayoutUnit collapsedLegendExtent;
     LayoutUnit innerBlockPadding;
-
-    if (legendLogicalHeight < fieldsetBorderBefore) {
-      // Center legend in fieldset border
+    // FIXME: We need to account for the legend's margin before too.
+    if (fieldsetBorderBefore > legendLogicalHeight) {
+      // The <legend> is smaller than the associated fieldset before border
+      // so the latter determines positioning of the <legend>. The sizing
+      // depends on the legend's margins as we want to still follow the
+      // author's cues.
+      // Firefox completely ignores the margins in this case which seems wrong.
       legendLogicalTop = (fieldsetBorderBefore - legendLogicalHeight) / 2;
+      collapsedLegendExtent = max<LayoutUnit>(
+          fieldsetBorderBefore, legendLogicalTop + legendLogicalHeight +
+                                    marginAfterForChild(*legend));
+      innerBlockPadding = marginAfterForChild(*legend)
+                              ? marginAfterForChild(*legend) - legendLogicalTop
+                              : LayoutUnit();
+    } else {
+      collapsedLegendExtent =
+          legendLogicalHeight + marginAfterForChild(*legend);
+      innerBlockPadding =
+          legendLogicalHeight - borderAfter() + marginAfterForChild(*legend);
     }
 
-    // Calculate how much legend + bottom margin sticks below the fieldset
-    // border
-    innerBlockPadding = (legendLogicalTop + legendLogicalHeight +
-                         marginAfterForChild(*legend) - fieldsetBorderBefore)
-                            .clampNegativeToZero();
-
-    if (legendLogicalTop < marginBeforeForChild(*legend)) {
-      // legend margin pushes everything down
-      innerBlockPadding += marginBeforeForChild(*legend) - legendLogicalTop;
-      legendLogicalTop = marginBeforeForChild(*legend);
-    }
-
-    collapsedLegendExtent =
-        std::max(fieldsetBorderBefore, marginBeforeForChild(*legend) +
-                                           legendLogicalHeight +
-                                           marginAfterForChild(*legend));
-
     if (m_innerBlock)
       setInnerBlockPadding(isHorizontalWritingMode(), m_innerBlock,
                            innerBlockPadding);