HTMLTextAreaElement.defaultValue is not implemented as per spec

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 395 matching lines @@
 }
 
 void HTMLTextAreaElement::setInnerEditorValue(const String& value)
 {
     HTMLTextFormControlElement::setInnerEditorValue(value);
     m_valueIsUpToDate = true;
 }
 
 String HTMLTextAreaElement::defaultValue() const
 {
-    StringBuilder value;
-
-    // Since there may be comments, ignore nodes other than text nodes.
-    for (Node* n = firstChild(); n; n = n->nextSibling()) {
-        if (n->isTextNode())
-            value.append(toText(n)->data());
-    }
-
-    return value.toString();
+    return textContent();
 }
 
 void HTMLTextAreaElement::setDefaultValue(const String& defaultValue)
 {
-    RefPtrWillBeRawPtr<Node> protectFromMutationEvents(this);
-
-    // To preserve comments, remove only the text nodes, then add a single text node.
-    WillBeHeapVector<RefPtrWillBeMember<Node>> textNodes;
-    for (Node* n = firstChild(); n; n = n->nextSibling()) {
-        if (n->isTextNode())
-            textNodes.append(n);
-    }
-    size_t size = textNodes.size();
-    for (size_t i = 0; i < size; ++i)
-        removeChild(textNodes[i].get(), IGNORE_EXCEPTION);
-
-    // Normalize line endings.
-    String value = defaultValue;
-    value.replace("\r\n", "\n");
-    value.replace('\r', '\n');
-
-    insertBefore(document().createTextNode(value), firstChild(), IGNORE_EXCEPTION);
-
+    setTextContent(defaultValue);
     if (!m_isDirty)

[Sunil Ratnu, 2015/07/10 07:47:26]

I tried using ImplementedAs=textContent in the idl as you can see in the
previous patchset but that results into failure of test case
"fast/forms/textarea-selection-preservation.html". The call to setNonDirtyValue
ensures that the textarea selection is preserved. Could you please let me know
if there are any issues with this call being here apart from the call to
setTextContent(). If there are any issues, I will try to come up with some
different approach.

[tkent, 2015/07/10 07:59:40]

Can you add test cases of ta.textContent = '...' to
textarea-selection-preservation.html, similar to existing ta.defaultValue =
'...'?  Do such test cases succeed?

When setTextContent is called, HTMLTextAreaElement::childrenChanged should be
called, then childrenChanged should call setNonDirtyValue.  I wonder why we
still need setNonDirtyValue here.

-        setNonDirtyValue(value);
+        setNonDirtyValue(defaultValue);
 }
 
 int HTMLTextAreaElement::maxLength() const
 {
     int value;
     if (!parseHTMLInteger(getAttribute(maxlengthAttr), value))
         return -1;
     return value >= 0 ? value : -1;
 }
 
@@ skipping 182 matching lines @@
 
 void HTMLTextAreaElement::copyNonAttributePropertiesFromElement(const Element& source)
 {
     const HTMLTextAreaElement& sourceElement = static_cast<const HTMLTextAreaElement&>(source);
     setValueCommon(sourceElement.value(), DispatchNoEvent, SetSeletion);
     m_isDirty = sourceElement.m_isDirty;
     HTMLTextFormControlElement::copyNonAttributePropertiesFromElement(source);
 }
 
 } // namespace blink