Avoid adding placeholder when deleting last text in root

Source/core/html/HTMLInputElement.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, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
@@ skipping 1035 matching lines @@
 void HTMLInputElement::setValueFromRenderer(const String& value)
 {
     // File upload controls will never use this.
     ASSERT(!isFileUpload());
 
     m_suggestedValue = String();
 
     // Renderer and our event handler are responsible for sanitizing values.
     ASSERT(value == sanitizeValue(value) || sanitizeValue(value).isEmpty());
 
-    // Workaround for bug where trailing \n is included in the result of textContent.
-    // The assert macro above may also be simplified to: value == constrainValue(value)
-    // http://bugs.webkit.org/show_bug.cgi?id=9661
-    m_valueIfDirty = value == "\n" ? emptyString() : value;
+    m_valueIfDirty = value;
 
     setFormControlValueMatchesRenderer(true);
     m_wasModifiedByUser = true;
 
     // Input event is fired by the Node::defaultEventHandler for editable controls.
     if (!isTextField())
         dispatchInputEvent();
     notifyFormStateChanged();
 
     setNeedsValidityCheck();
@@ skipping 812 matching lines @@
 }
 
 #if ENABLE(INPUT_MULTIPLE_FIELDS_UI)
 PassRefPtr<RenderStyle> HTMLInputElement::customStyleForRenderer()
 {
     return m_inputType->customStyleForRenderer(document()->styleResolver()->styleForElement(this));
 }
 #endif
 
 } // namespace