CSS4: Implement :placeholder-shown pseudo class

Source/core/html/HTMLTextFormControlElement.cpp

Index: Source/core/html/HTMLTextFormControlElement.cpp
diff --git a/Source/core/html/HTMLTextFormControlElement.cpp b/Source/core/html/HTMLTextFormControlElement.cpp
index 5e180c36bcb567e2f04dc97a2c729b88ba700cea..7cf1d85f7da3796e79f49ad481b216fc135b96a5 100644
--- a/Source/core/html/HTMLTextFormControlElement.cpp
+++ b/Source/core/html/HTMLTextFormControlElement.cpp
@@ -83,7 +83,7 @@ Node::InsertionNotificationRequest HTMLTextFormControlElement::insertedInto(Cont
 void HTMLTextFormControlElement::dispatchFocusEvent(Element* oldFocusedElement, WebFocusType type, InputDeviceCapabilities* sourceCapabilities)
 {
     if (supportsPlaceholder())
-        updatePlaceholderVisibility(false);
+        updatePlaceholderVisibility();
     handleFocusEvent(oldFocusedElement, type);
     HTMLFormControlElementWithState::dispatchFocusEvent(oldFocusedElement, type, sourceCapabilities);
 }
@@ -91,7 +91,7 @@ void HTMLTextFormControlElement::dispatchFocusEvent(Element* oldFocusedElement,
 void HTMLTextFormControlElement::dispatchBlurEvent(Element* newFocusedElement, WebFocusType type, InputDeviceCapabilities* sourceCapabilities)
 {
     if (supportsPlaceholder())
-        updatePlaceholderVisibility(false);
+        updatePlaceholderVisibility();
     handleBlurEvent();
     HTMLFormControlElementWithState::dispatchBlurEvent(newFocusedElement, type, sourceCapabilities);
 }
@@ -147,8 +147,7 @@ bool HTMLTextFormControlElement::placeholderShouldBeVisible() const
     return supportsPlaceholder()
         && isEmptyValue()
         && isEmptySuggestedValue()
-        && !isPlaceholderEmpty()
-        && (!layoutObject() || layoutObject()->style()->visibility() == VISIBLE);
+        && !isPlaceholderEmpty();
 }
 
 HTMLElement* HTMLTextFormControlElement::placeholderElement() const
@@ -156,17 +155,21 @@ HTMLElement* HTMLTextFormControlElement::placeholderElement() const
     return toHTMLElement(userAgentShadowRoot()->getElementById(ShadowElementNames::placeholder()));
 }
 
-void HTMLTextFormControlElement::updatePlaceholderVisibility(bool placeholderValueChanged)
+void HTMLTextFormControlElement::updatePlaceholderVisibility()
 {
-    if (!supportsPlaceholder())
-        return;
-    if (!placeholderElement() || placeholderValueChanged)
-        updatePlaceholderText();
     HTMLElement* placeholder = placeholderElement();
-    if (!placeholder)
+    if (!placeholder) {
+        updatePlaceholderText();
         return;
+    }
 
-    placeholder->setInlineStyleProperty(CSSPropertyDisplay, placeholderShouldBeVisible() ? CSSValueBlock : CSSValueNone);
+    bool placeHolderWasVisible = isPlaceholderVisible();
+    setPlaceholderVisibility(placeholderShouldBeVisible());
+    if (placeHolderWasVisible == isPlaceholderVisible())
+        return;
+
+    pseudoStateChanged(CSSSelector::PseudoPlaceholderShown);
+    placeholder->setInlineStyleProperty(CSSPropertyDisplay, isPlaceholderVisible() ? CSSValueBlock : CSSValueNone, true);
 }
 
 void HTMLTextFormControlElement::setSelectionStart(int start)
@@ -607,7 +610,8 @@ void HTMLTextFormControlElement::parseAttribute(const QualifiedName& name, const
         UseCounter::count(document(), UseCounter::AutocapitalizeAttribute);
 
     if (name == placeholderAttr) {
-        updatePlaceholderVisibility(true);
+        updatePlaceholderText();
+        updatePlaceholderVisibility();
         UseCounter::count(document(), UseCounter::PlaceholderAttribute);
     } else {
         HTMLFormControlElementWithState::parseAttribute(name, value);