Remove HTMLFormControlElement::m_disabled, m_isReadOnly, and m_isRequired.

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

Index: third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp b/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
index cd7c635bd7043f6e6117e15a99236bc77c855474..5cfa24813f52ed0a8ad47c601ea6082773f6c142 100644
--- a/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
@@ -49,10 +49,7 @@ using namespace HTMLNames;
 
 HTMLFormControlElement::HTMLFormControlElement(const QualifiedName& tagName, Document& document, HTMLFormElement* form)
     : LabelableElement(tagName, document)
-    , m_disabled(false)
     , m_isAutofilled(false)
-    , m_isReadOnly(false)
-    , m_isRequired(false)
     , m_hasValidationMessage(false)
     , m_ancestorDisabledState(AncestorDisabledStateUnknown)
     , m_dataListAncestorState(Unknown)
@@ -163,14 +160,10 @@ void HTMLFormControlElement::parseAttribute(const QualifiedName& name, const Ato
         formAttributeChanged();
         UseCounter::count(document(), UseCounter::FormAttribute);
     } else if (name == disabledAttr) {
-        bool oldDisabled = m_disabled;
-        m_disabled = !value.isNull();
-        if (oldDisabled != m_disabled)
+        if (oldValue.isNull() != value.isNull())
             disabledAttributeChanged();
     } else if (name == readonlyAttr) {
-        bool wasReadOnly = m_isReadOnly;
-        m_isReadOnly = !value.isNull();
-        if (wasReadOnly != m_isReadOnly) {
+        if (oldValue.isNull() != value.isNull()) {
             setNeedsWillValidateCheck();
             pseudoStateChanged(CSSSelector::PseudoReadOnly);
             pseudoStateChanged(CSSSelector::PseudoReadWrite);
@@ -178,9 +171,7 @@ void HTMLFormControlElement::parseAttribute(const QualifiedName& name, const Ato
                 LayoutTheme::theme().controlStateChanged(*layoutObject(), ReadOnlyControlState);
         }
     } else if (name == requiredAttr) {
-        bool wasRequired = m_isRequired;
-        m_isRequired = !value.isNull();
-        if (wasRequired != m_isRequired)
+        if (oldValue.isNull() != value.isNull())
             requiredAttributeChanged();
         UseCounter::count(document(), UseCounter::RequiredAttribute);
     } else if (name == autofocusAttr) {
@@ -356,7 +347,7 @@ HTMLFormElement* HTMLFormControlElement::formOwner() const
 
 bool HTMLFormControlElement::isDisabledFormControl() const
 {
-    if (m_disabled)
+    if (fastHasAttribute(disabledAttr))
         return true;
 
     if (m_ancestorDisabledState == AncestorDisabledStateUnknown)
@@ -366,7 +357,7 @@ bool HTMLFormControlElement::isDisabledFormControl() const
 
 bool HTMLFormControlElement::isRequired() const
 {
-    return m_isRequired;
+    return fastHasAttribute(requiredAttr);
 }
 
 String HTMLFormControlElement::resultForDialogSubmit()