Button elements are clipping overflow by default

Source/core/layout/LayoutButton.cpp

 /**
  * Copyright (C) 2005 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 85 matching lines @@
         // even when we have the anonymous LayoutBlock child, we calculate the
         // baseline for the empty case manually here.
         if (direction == HorizontalLine) {
             return marginTop() + size().height() - borderBottom() - paddingBottom() - horizontalScrollbarHeight();
         }
         return marginRight() + size().width() - borderLeft() - paddingLeft() - verticalScrollbarWidth();
     }
     return LayoutFlexibleBox::baselinePosition(baseline, firstLine, direction, linePositionMode);
 }
 
+
+// For compatibility with IE/FF we only clip overflow on input elements.
+bool LayoutButton::hasControlClip() const
+{
+    return !isHTMLButtonElement(node());
+}
 } // namespace blink