Introduce HTMLInputElement::m_hasDirtyValue.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * 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 101 matching lines @@
 
     void setType(const AtomicString&);
 
     String value() const override;
     void setValue(const String&, ExceptionState&, TextFieldEventBehavior = DispatchNoEvent);
     void setValue(const String&, TextFieldEventBehavior = DispatchNoEvent) override;
     void setValueForUser(const String&);
     // Checks if the specified string would be a valid value.
     // We should not call this for types with no string value such as CHECKBOX and RADIO.
     bool isValidValue(const String&) const;
-    bool hasDirtyValue() const { return !m_valueIfDirty.isNull(); }
+    bool hasDirtyValue() const;
 
     String sanitizeValue(const String&) const;
 
     String localizeValue(const String&) const;
 
     const String& suggestedValue() const;
     void setSuggestedValue(const String&);
 
     void setEditingValue(const String&);
 
@@ skipping 234 matching lines @@
 
     // Returns null if this isn't associated with any radio button group.
     RadioButtonGroupScope* radioButtonGroupScope() const;
     void addToRadioButtonGroup();
     void removeFromRadioButtonGroup();
     PassRefPtr<ComputedStyle> customStyleForLayoutObject() override;
 
     bool shouldDispatchFormControlChangeEvent(String&, String&) override;
 
     AtomicString m_name;
+    // A dirty value.  isNull() means the value is not dirty and we should refer
+    // to |value| content attribute value.
     String m_valueIfDirty;
     String m_suggestedValue;
     int m_size;
     int m_maxLength;
     int m_minLength;
+    // https://html.spec.whatwg.org/multipage/forms.html#concept-input-value-dirty-flag
+    unsigned m_hasDirtyValue : 1;
     // https://html.spec.whatwg.org/multipage/forms.html#concept-fe-checked
     unsigned m_isChecked : 1;
     // https://html.spec.whatwg.org/multipage/forms.html#concept-input-checked-dirty-flag
     unsigned m_dirtyCheckedness : 1;
     unsigned m_isIndeterminate : 1;
     unsigned m_isActivatedSubmit : 1;
     unsigned m_autocomplete : 2; // AutoCompleteSetting
     unsigned m_hasNonEmptyList : 1;
     unsigned m_stateRestored : 1;
     unsigned m_parsingInProgress : 1;
     unsigned m_valueAttributeWasUpdatedAfterParsing : 1;
     unsigned m_canReceiveDroppedFiles : 1;
     unsigned m_shouldRevealPassword : 1;
     unsigned m_needsToUpdateViewValue : 1;
     unsigned m_isPlaceholderVisible : 1;
     Member<InputType> m_inputType;
     Member<InputTypeView> m_inputTypeView;
     // The ImageLoader must be owned by this element because the loader code assumes
     // that it lives as long as its owning element lives. If we move the loader into
     // the ImageInput object we may delete the loader while this element lives on.
     Member<HTMLImageLoader> m_imageLoader;
     Member<ListAttributeTargetObserver> m_listAttributeTargetObserver;
 };
 
 } // namespace blink
 
 #endif // HTMLInputElement_h