CSS4: Implement :placeholder-shown pseudo class

Source/core/testing/Internals.cpp

Index: Source/core/testing/Internals.cpp
diff --git a/Source/core/testing/Internals.cpp b/Source/core/testing/Internals.cpp
index 9dd1de88e29323a343b9ed150a9794c91e4c00f0..af87ede48e03a4e61c94745769168508d10712ef 100644
--- a/Source/core/testing/Internals.cpp
+++ b/Source/core/testing/Internals.cpp
@@ -688,8 +688,11 @@ const AtomicString& Internals::shadowPseudoId(Element* element)
 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();