Fix bug where form/fieldset :valid/:invalid won't be recalculated upon control's willValidate change

Source/core/html/HTMLFormControlElement.cpp

Index: Source/core/html/HTMLFormControlElement.cpp
diff --git a/Source/core/html/HTMLFormControlElement.cpp b/Source/core/html/HTMLFormControlElement.cpp
index 6605a6d7de08c0626db248818e31c90a55d09c40..4cfd32a68302c1d97ef27e5ec375200819114359 100644
--- a/Source/core/html/HTMLFormControlElement.cpp
+++ b/Source/core/html/HTMLFormControlElement.cpp
@@ -263,27 +263,28 @@ void HTMLFormControlElement::removedFrom(ContainerNode* insertionPoint)
     m_hasValidationMessage = false;
     m_ancestorDisabledState = AncestorDisabledStateUnknown;
     m_dataListAncestorState = Unknown;
+    setNeedsWillValidateCheck();
     HTMLElement::removedFrom(insertionPoint);
     FormAssociatedElement::removedFrom(insertionPoint);
 }
 
 void HTMLFormControlElement::willChangeForm()
 {
-    formOwnerSetNeedsValidityCheck();
     FormAssociatedElement::willChangeForm();
+    formOwnerSetNeedsValidityCheck(ElementRemoval, isValidElement());
 }
 
 void HTMLFormControlElement::didChangeForm()
 {
-    formOwnerSetNeedsValidityCheck();
     FormAssociatedElement::didChangeForm();
+    formOwnerSetNeedsValidityCheck(ElementAddition, isValidElement());
 }
 
-void HTMLFormControlElement::formOwnerSetNeedsValidityCheck()
+void HTMLFormControlElement::formOwnerSetNeedsValidityCheck(ValidityRecalcReason reason, bool isValid)
 {
     HTMLFormElement* form = formOwner();
     if (form)
-        form->setNeedsValidityCheck();
+        form->setNeedsValidityCheck(reason, isValid);
 }
 
 void HTMLFormControlElement::fieldSetAncestorsSetNeedsValidityCheck(Node* node)
@@ -406,12 +407,7 @@ bool HTMLFormControlElement::recalcWillValidate() const
 bool HTMLFormControlElement::willValidate() const
 {
     if (!m_willValidateInitialized || m_dataListAncestorState == Unknown) {
-        m_willValidateInitialized = true;
-        bool newWillValidate = recalcWillValidate();
-        if (m_willValidate != newWillValidate) {
-            m_willValidate = newWillValidate;
-            const_cast<HTMLFormControlElement*>(this)->setNeedsValidityCheck();
-        }
+        const_cast<HTMLFormControlElement*>(this)->setNeedsWillValidateCheck(false);

[tkent, 2014/11/07 00:15:19]

Why do we need to pass |false| here?  I think validation message is not visible
in this case, and calling hideVisibleValidationMessage() in
setNeedsWillValidateCheck() is harmless.

[Bartek Nowierski, 2014/11/12 22:23:57]

We added this to make the new code behave exactly like the old code. This way we
don't call an extra hideVisibleValidationMessage() if we don't need to. But I'll
be happy to remove it. It will simplify things :)

     } else {
         // If the following assertion fails, setNeedsWillValidateCheck() is not
         // called correctly when something which changes recalcWillValidate() result
@@ -421,7 +417,7 @@ bool HTMLFormControlElement::willValidate() const
     return m_willValidate;
 }
 
-void HTMLFormControlElement::setNeedsWillValidateCheck()
+void HTMLFormControlElement::setNeedsWillValidateCheck(bool hideValidationMessageIfNeeded)
 {
     // We need to recalculate willValidate immediately because willValidate change can causes style change.
     bool newWillValidate = recalcWillValidate();
@@ -430,8 +426,11 @@ void HTMLFormControlElement::setNeedsWillValidateCheck()
     m_willValidateInitialized = true;
     m_willValidate = newWillValidate;
     setNeedsValidityCheck();
-    setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::Validate));
-    if (!m_willValidate)
+    // No need to trigger style recalculation here because
+    // setNeedsValidityCheck() does it in the right away. This relies on
+    // the assumption that valid() is always true if willValidate() is false.
+
+    if (hideValidationMessageIfNeeded && !m_willValidate)
         hideVisibleValidationMessage();
 }
 
@@ -557,14 +556,15 @@ bool HTMLFormControlElement::isValidElement()
 void HTMLFormControlElement::setNeedsValidityCheck()
 {
     bool newIsValid = valid();
-    if (willValidate() && newIsValid != m_isValid) {
-        formOwnerSetNeedsValidityCheck();
+    bool changed = newIsValid != m_isValid;
+    m_isValid = newIsValid;
+    if (changed) {
+        formOwnerSetNeedsValidityCheck(ElementModification, newIsValid);
         fieldSetAncestorsSetNeedsValidityCheck(parentNode());
         // Update style for pseudo classes such as :valid :invalid.
         pseudoStateChanged(CSSSelector::PseudoValid);
         pseudoStateChanged(CSSSelector::PseudoInvalid);
     }
-    m_isValid = newIsValid;
 
     // Updates only if this control already has a validation message.
     if (isValidationMessageVisible()) {