Revert "Revert of Fix update of validity cache value, so that it reflects the correct state of any …

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 404 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 (willValidate()) {
         // Update style for pseudo classes such as :valid :invalid.
-        setNeedsStyleRecalc(SubtreeStyleChange);
+        if (valid() != m_isValid)

[tkent, 2014/09/25 05:35:55]

This is incorrect. Because setNeedsValidityCheck() can be called before all of
state changes are completed, valid() here may return an incorrect result, and we
might miss a necessary setNeedsStyleRecalc() call.

If style recalc cost is much larger than validation cost, a solution would be to
remove the validity lazy evaluation and the validity cache, and call valid()
every time.  This also can cause performance regression of
DOM/textarea-{dom,edit}.html performance tests.

[spartha, 2014/09/25 06:38:05]

As you suggest removing the validity cache should be fine. But actual issue is
with the style recalc. The tricky part is we need style recalc to update the
control's state, and we should avoid over doing it for performance. I cannot
think of a more reliable way to restrict the number style recalcs.

+            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 blink