CSS4: Implement :placeholder-shown pseudo class

Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 670 matching lines @@
 
 const AtomicString& Internals::shadowPseudoId(Element* element)
 {
     ASSERT(element);
     return element->shadowPseudoId();
 }
 
 String Internals::visiblePlaceholder(Element* element)
 {
     if (element && isHTMLTextFormControlElement(*element)) {
-        if (toHTMLTextFormControlElement(element)->placeholderShouldBeVisible())
-            return toHTMLTextFormControlElement(element)->placeholderElement()->textContent();
+        const HTMLTextFormControlElement& textFormControlElement = toHTMLTextFormControlElement(*element);
+        if (!textFormControlElement.isPlaceholderVisible())
+            return String();
+        if (HTMLElement* placeholderElement = textFormControlElement.placeholderElement())
+            return placeholderElement->textContent();
     }
 
     return String();
 }
 
 void Internals::selectColorInColorChooser(Element* element, const String& colorValue)
 {
     ASSERT(element);
     if (!isHTMLInputElement(*element))
         return;
@@ skipping 1776 matching lines @@
 
     return animator->setScrollbarsVisibleForTesting(visible);
 }
 
 void Internals::forceRestrictIFramePermissions()
 {
     RuntimeEnabledFeatures::setRestrictIFramePermissionsEnabled(true);
 }
 
 } // namespace blink