CSS4: Implement :placeholder-shown pseudo class

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 682 matching lines @@
             if (value.isEmpty())
                 m_autocomplete = Uninitialized;
             else
                 m_autocomplete = On;
         }
     } else if (name == typeAttr) {
         updateType();
     } else if (name == valueAttr) {
         // We only need to setChanged if the form is looking at the default value right now.
         if (!hasDirtyValue()) {
-            updatePlaceholderVisibility(false);
+            updatePlaceholderVisibility();
             setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::fromAttribute(valueAttr));
         }
         m_needsToUpdateViewValue = true;
         setNeedsValidityCheck();
         m_valueAttributeWasUpdatedAfterParsing = !m_parsingInProgress;
         m_inputType->warnIfValueIsInvalidAndElementIsVisible(value);
         m_inputTypeView->valueAttributeChanged();
     } else if (name == checkedAttr) {
         // Another radio button in the same group might be checked by state
         // restore. We shouldn't call setChecked() even if this has the checked
@@ skipping 1211 matching lines @@
 void HTMLInputElement::ensurePrimaryContent()
 {
     m_inputTypeView->ensurePrimaryContent();
 }
 
 bool HTMLInputElement::hasFallbackContent() const
 {
     return m_inputTypeView->hasFallbackContent();
 }
 } // namespace