Let Node.textContent never throw

Source/core/html/HTMLTextAreaElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 506 matching lines @@
             userAgentShadowRoot()->removeChild(placeholder);
         return;
     }
     if (!placeholder) {
         RefPtr<HTMLDivElement> newElement = HTMLDivElement::create(document());
         placeholder = newElement.get();
         placeholder->setPseudo(AtomicString("-webkit-input-placeholder", AtomicString::ConstructFromLiteral));
         placeholder->setAttribute(idAttr, ShadowElementNames::placeholder());
         userAgentShadowRoot()->insertBefore(placeholder, innerTextElement()->nextSibling());
     }
-    placeholder->setTextContent(placeholderText, ASSERT_NO_EXCEPTION);
+    placeholder->setTextContent(placeholderText);
 }
 
 bool HTMLTextAreaElement::isInteractiveContent() const
 {
     return true;
 }
 
 }