Fix update of validity cache value, so that it reflects the correct state of any FormControlElement.

Source/core/html/HTMLFormControlElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 40 matching lines @@
     , m_disabled(false)
     , m_isAutofilled(false)
     , m_isReadOnly(false)
     , m_isRequired(false)
     , m_hasValidationMessage(false)
     , m_ancestorDisabledState(AncestorDisabledStateUnknown)
     , m_dataListAncestorState(Unknown)
     , m_willValidateInitialized(false)
     , m_willValidate(true)
     , m_isValid(true)
+    , m_validityIsDirty(true)
     , m_wasChangedSinceLastFormControlChangeEvent(false)
     , m_wasFocusedByMouse(false)
 {
     setHasCustomStyleCallbacks();
     associateByParser(form);
 }
 
 HTMLFormControlElement::~HTMLFormControlElement()
 {
 #if !ENABLE(OILPAN)
@@ skipping 395 matching lines @@
     RefPtrWillBeRawPtr<HTMLFormControlElement> protector(this);
     RefPtrWillBeRawPtr<Document> originalDocument(document());
     bool needsDefaultAction = dispatchEvent(Event::createCancelable(EventTypeNames::invalid));
     if (needsDefaultAction && unhandledInvalidControls && inDocument() && originalDocument == document())
         unhandledInvalidControls->append(this);
     return false;
 }
 
 bool HTMLFormControlElement::isValidFormControlElement()
 {
-    // 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 = 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 == valid());
+    }
     return m_isValid;
 }
 
 void HTMLFormControlElement::setNeedsValidityCheck()
 {
-    bool newIsValid = valid();
-    if (willValidate() && newIsValid != m_isValid) {
+    if (!m_validityIsDirty && willValidate()) {
         // Update style for pseudo classes such as :valid :invalid.
         setNeedsStyleRecalc(SubtreeStyleChange);
+        m_validityIsDirty = true;
     }
-    m_isValid = newIsValid;
 
     // Updates only if this control already has a validation message.
     if (isValidationMessageVisible()) {
         // Calls updateVisibleValidationMessage() even if m_isValid is not
         // changed because a validation message can be changed.
         updateVisibleValidationMessage();
     }
 }
 
 void HTMLFormControlElement::setCustomValidity(const String& error)
@@ skipping 38 matching lines @@
 
 void HTMLFormControlElement::setFocus(bool flag)
 {
     LabelableElement::setFocus(flag);
 
     if (!flag && wasChangedSinceLastFormControlChangeEvent())
         dispatchFormControlChangeEvent();
 }
 
 } // namespace Webcore