Simplify form validation handling

This CL contains some part of https://codereview.chromium.org/460343004/ by
sudarshan.p, which was reverted by a performance regression.

This CL simplifies form validation state handling code by
 - lazy update of m_isValid
   setNeedsValidityCheck just makes m_isValid dirty.
 - m_isValid takes care of willValidate state too.
   m_isValid = !willValidate() || valid()

We switched to invalidation sets for :valid and :invalid by Blink
r184392. Calling pseudoStateChanged() for unchanged validity state won't have so
bad performance. So, we can evaluate m_isValid lazily.

We need to change the meaning of m_isValid slightly so that it takes care of
willValidate(). This is necessary to clean m_validityIsDirty of associated
controls in HTMLFormElement::checkInvalidControlsAndCollectUnhandled.
Without this change, there would be a case where willValidate state
change won't invalidate :valid :invalid style of <form>.

This CL will have a few percent regression on blink_perf.dom:textarea-edit.
A fix for the performance regression will be landed soon.

BUG=

Review URL: https://codereview.chromium.org/943303002

git-svn-id: svn://svn.chromium.org/blink/trunk@190723 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/html/HTMLFieldSetElement.cpp

@@ -76,15 +76,6 @@ bool HTMLFieldSetElement::isValidElement()
     return true;
 }
 
-void HTMLFieldSetElement::setNeedsValidityCheck()
-{
-    // For now unconditionally order style recalculation, which triggers
-    // validity recalculation. In the near future, consider implement validity
-    // cache and recalculate style only if it changed.
-    pseudoStateChanged(CSSSelector::PseudoValid);
-    pseudoStateChanged(CSSSelector::PseudoInvalid);
-}
-
 void HTMLFieldSetElement::invalidateDisabledStateUnder(Element& base)
 {
     for (HTMLFormControlElement& element : Traversal<HTMLFormControlElement>::descendantsOf(base))

third_party/WebKit/Source/core/html/HTMLFieldSetElement.h

@@ -41,8 +41,6 @@ public:
 
     const FormAssociatedElement::List& associatedElements() const;
 
-    void setNeedsValidityCheck();
-
 protected:
     virtual void disabledAttributeChanged() override;
 

third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp

@@ -58,6 +58,7 @@ HTMLFormControlElement::HTMLFormControlElement(const QualifiedName& tagName, Doc
     , m_willValidateInitialized(false)
     , m_willValidate(true)
     , m_isValid(true)
+    , m_validityIsDirty(false)
     , m_wasChangedSinceLastFormControlChangeEvent(false)
     , m_wasFocusedByMouse(false)
 {
@@ -283,28 +284,31 @@ void HTMLFormControlElement::removedFrom(ContainerNode* insertionPoint)
 void HTMLFormControlElement::willChangeForm()
 {
     FormAssociatedElement::willChangeForm();
-    formOwnerSetNeedsValidityCheck(ElementRemoval, isValidElement());
+    formOwnerSetNeedsValidityCheck();
 }
 
 void HTMLFormControlElement::didChangeForm()
 {
     FormAssociatedElement::didChangeForm();
-    formOwnerSetNeedsValidityCheck(ElementAddition, isValidElement());
+    formOwnerSetNeedsValidityCheck();
 }
 
-void HTMLFormControlElement::formOwnerSetNeedsValidityCheck(ValidityRecalcReason reason, bool isValid)
+void HTMLFormControlElement::formOwnerSetNeedsValidityCheck()
 {
-    HTMLFormElement* form = formOwner();
-    if (form)
-        form->setNeedsValidityCheck(reason, isValid);
+    if (HTMLFormElement* form = formOwner()) {
+        form->pseudoStateChanged(CSSSelector::PseudoValid);
+        form->pseudoStateChanged(CSSSelector::PseudoInvalid);
+    }
 }
 
 void HTMLFormControlElement::fieldSetAncestorsSetNeedsValidityCheck(Node* node)
 {
     if (!node)
         return;
-    for (HTMLFieldSetElement* fieldSet = Traversal<HTMLFieldSetElement>::firstAncestorOrSelf(*node); fieldSet; fieldSet = Traversal<HTMLFieldSetElement>::firstAncestor(*fieldSet))
-        fieldSet->setNeedsValidityCheck();
+    for (HTMLFieldSetElement* fieldSet = Traversal<HTMLFieldSetElement>::firstAncestorOrSelf(*node); fieldSet; fieldSet = Traversal<HTMLFieldSetElement>::firstAncestor(*fieldSet)) {
+        fieldSet->pseudoStateChanged(CSSSelector::PseudoValid);
+        fieldSet->pseudoStateChanged(CSSSelector::PseudoInvalid);
+    }
 }
 
 void HTMLFormControlElement::setChangedSinceLastFormControlChangeEvent(bool changed)
@@ -508,7 +512,7 @@ ValidationMessageClient* HTMLFormControlElement::validationMessageClient() const
 
 bool HTMLFormControlElement::checkValidity(WillBeHeapVector<RefPtrWillBeMember<HTMLFormControlElement>>* unhandledInvalidControls, CheckValidityEventBehavior eventBehavior)
 {
-    if (!willValidate() || isValidElement())
+    if (isValidElement())
         return true;
     if (eventBehavior != CheckValidityDispatchInvalidEvent)
         return false;
@@ -559,21 +563,23 @@ bool HTMLFormControlElement::matchesValidityPseudoClasses() const
 
 bool HTMLFormControlElement::isValidElement()
 {
-    // If the following assertion fails, setNeedsValidityCheck() is not called
-    // correctly when something which changes validity is updated.
-    ASSERT(m_isValid == valid());
+    if (m_validityIsDirty) {
+        m_isValid = !willValidate() || valid();
+        m_validityIsDirty = false;
+    } else {
+        // If the following assertion fails, setNeedsValidityCheck() is not
+        // called correctly when something which changes validity is updated.
+        ASSERT(m_isValid == (!willValidate() || valid()));
+    }
     return m_isValid;
 }
 
 void HTMLFormControlElement::setNeedsValidityCheck()
 {
-    bool newIsValid = valid();
-    bool changed = newIsValid != m_isValid;
-    m_isValid = newIsValid;
-    if (changed) {
-        formOwnerSetNeedsValidityCheck(ElementModification, newIsValid);
+    if (!m_validityIsDirty) {
+        m_validityIsDirty = true;
+        formOwnerSetNeedsValidityCheck();
         fieldSetAncestorsSetNeedsValidityCheck(parentNode());
-        // Update style for pseudo classes such as :valid :invalid.
         pseudoStateChanged(CSSSelector::PseudoValid);
         pseudoStateChanged(CSSSelector::PseudoInvalid);
     }

third_party/WebKit/Source/core/html/HTMLFormControlElement.h

@@ -34,7 +34,6 @@ class HTMLFormElement;
 class ValidationMessageClient;
 
 enum CheckValidityEventBehavior { CheckValidityDispatchNoEvent, CheckValidityDispatchInvalidEvent };
-enum ValidityRecalcReason { ElementAddition, ElementRemoval, ElementModification };
 
 // HTMLFormControlElement is the default implementation of FormAssociatedElement,
 // and form-associated element implementations should use HTMLFormControlElement
@@ -169,9 +168,7 @@ private:
     ValidationMessageClient* validationMessageClient() const;
 
     // Requests validity recalc for the form owner, if one exists.
-    // In case of removal, isValid specifies element validity upon removal.
-    // In case of addition and modification, it specifies new validity.
-    void formOwnerSetNeedsValidityCheck(ValidityRecalcReason, bool isValid);
+    void formOwnerSetNeedsValidityCheck();
     // Requests validity recalc for all ancestor fieldsets, if exist.
     void fieldSetAncestorsSetNeedsValidityCheck(Node*);
 
@@ -193,8 +190,8 @@ private:
     mutable bool m_willValidate : 1;
 
     // Cache of valid().
-    // But "candidate for constraint validation" doesn't affect m_isValid.
     bool m_isValid : 1;
+    bool m_validityIsDirty : 1;
 
     bool m_wasChangedSinceLastFormControlChangeEvent : 1;
     bool m_wasFocusedByMouse : 1;

third_party/WebKit/Source/core/html/HTMLFormElement.cpp

@@ -78,7 +78,6 @@ HTMLFormElement::HTMLFormElement(Document& document)
     , m_shouldSubmit(false)
     , m_isInResetFunction(false)
     , m_wasDemoted(false)
-    , m_invalidControlsCount(0)
     , m_pendingAutocompleteEventsQueue(GenericEventQueue::create(this))
 {
 }
@@ -714,31 +713,6 @@ HTMLFormControlElement* HTMLFormElement::defaultButton() const
     return 0;
 }
 
-void HTMLFormElement::setNeedsValidityCheck(ValidityRecalcReason reason, bool isValid)
-{
-    bool formWasInvalid = m_invalidControlsCount > 0;
-    switch (reason) {
-    case ElementRemoval:
-        if (!isValid)
-            --m_invalidControlsCount;
-        break;
-    case ElementAddition:
-        if (!isValid)
-            ++m_invalidControlsCount;
-        break;
-    case ElementModification:
-        if (isValid)
-            --m_invalidControlsCount;
-        else
-            ++m_invalidControlsCount;
-        break;
-    }
-    if (formWasInvalid && !m_invalidControlsCount)
-        pseudoStateChanged(CSSSelector::PseudoValid);
-    if (!formWasInvalid && m_invalidControlsCount)
-        pseudoStateChanged(CSSSelector::PseudoInvalid);
-}
-
 bool HTMLFormElement::checkValidity()
 {
     return !checkInvalidControlsAndCollectUnhandled(0, CheckValidityDispatchInvalidEvent);
@@ -746,9 +720,6 @@ bool HTMLFormElement::checkValidity()
 
 bool HTMLFormElement::checkInvalidControlsAndCollectUnhandled(WillBeHeapVector<RefPtrWillBeMember<HTMLFormControlElement>>* unhandledInvalidControls, CheckValidityEventBehavior eventBehavior)
 {
-    if (!unhandledInvalidControls && eventBehavior == CheckValidityDispatchNoEvent)
-        return m_invalidControlsCount;
-
     RefPtrWillBeRawPtr<HTMLFormElement> protector(this);
     // Copy associatedElements because event handlers called from
     // HTMLFormControlElement::checkValidity() might change associatedElements.
@@ -761,12 +732,13 @@ bool HTMLFormElement::checkInvalidControlsAndCollectUnhandled(WillBeHeapVector<R
     for (unsigned i = 0; i < elements.size(); ++i) {
         if (elements[i]->form() == this && elements[i]->isFormControlElement()) {
             HTMLFormControlElement* control = toHTMLFormControlElement(elements[i].get());
-            if (!control->checkValidity(unhandledInvalidControls, eventBehavior) && control->formOwner() == this)
+            if (!control->checkValidity(unhandledInvalidControls, eventBehavior) && control->formOwner() == this) {
                 ++invalidControlsCount;
+                if (!unhandledInvalidControls && eventBehavior == CheckValidityDispatchNoEvent)
+                    return true;
+            }
         }
     }
-    if (eventBehavior == CheckValidityDispatchNoEvent)
-        ASSERT(invalidControlsCount == m_invalidControlsCount);
     return invalidControlsCount;
 }
 

third_party/WebKit/Source/core/html/HTMLFormElement.h

@@ -48,8 +48,6 @@ public:
     virtual ~HTMLFormElement();
     DECLARE_VIRTUAL_TRACE();
 
-    void setNeedsValidityCheck(ValidityRecalcReason, bool isValid);
-
     PassRefPtrWillBeRawPtr<HTMLFormControlsCollection> elements();
     void getNamedElements(const AtomicString&, WillBeHeapVector<RefPtrWillBeMember<Element>>&);
 
@@ -186,10 +184,6 @@ private:
 
     bool m_wasDemoted : 1;
 
-    // Number of invalid elements associated to the form that are candidates
-    // for constraint validation (their willValidate state is true).
-    int m_invalidControlsCount;
-
     OwnPtrWillBeMember<GenericEventQueue> m_pendingAutocompleteEventsQueue;
 };