TEXTAREA: Cutting last line without EOL should not remove the remaining EOL in the previous line.

third_party/WebKit/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 255 matching lines @@
 }
 
 void HTMLTextAreaElement::handleFocusEvent(Element*, WebFocusType)
 {
     if (LocalFrame* frame = document().frame())
         frame->spellChecker().didBeginEditing(this);
 }
 
 void HTMLTextAreaElement::subtreeHasChanged()
 {
+#if ENABLE(ASSERT)
+    // The innerEditor should have either Text nodes or a placeholder break
+    // element. If we see other nodes, it's a bug in editing code and we should
+    // fix it.
+    Element* innerEditor = innerEditorElement();
+    for (Node& node : NodeTraversal::descendantsOf(*innerEditor)) {
+        if (node.isTextNode())
+            continue;
+        ASSERT(isHTMLBRElement(node));
+        ASSERT(&node == innerEditor->lastChild());
+    }
+#endif
+    addPlaceholderBreakElementIfNecessary();
     setChangedSinceLastFormControlChangeEvent(true);
     m_valueIsUpToDate = false;
     setNeedsValidityCheck();
     setAutofilled(false);
     updatePlaceholderVisibility();
 
     if (!focused())
         return;
 
     // When typing in a textarea, childrenChanged is not called, so we need to force the directionality check.
@@ skipping 363 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