Add hasDataList() method to HTMLInputElement.

https://bugs.webkit.org/show_bug.cgi?id=287537

Reviewed by NOBODY (OOPS!).

This reserves list() for use in bindings, and dataList() for internal use.

Once referenceTarget is implemented, dataList() will be used to retrieve the
list-associated element, which may be inside a shadow root, while list() may
return null (see WICG/webcomponents#1072 for
discussion).

hasDataList() checks whether a list-associated element is present, without
risking leaking shadow root internals inappropriately.

* Source/WebCore/accessibility/AccessibilityObject.cpp:
(WebCore::AccessibilityObject::hasDatalist const):
* Source/WebCore/html/HTMLInputElement.cpp:
(WebCore::HTMLInputElement::hasDataList const):
* Source/WebCore/html/HTMLInputElement.h:
* Source/WebCore/html/TextFieldInputType.cpp:
(WebCore::TextFieldInputType::handleClickEvent):
(WebCore::TextFieldInputType::showPicker):
(WebCore::TextFieldInputType::createShadowSubtree):
(WebCore::TextFieldInputType::didSetValueByUserEdit):
(WebCore::TextFieldInputType::dataListMayHaveChanged):
(WebCore::TextFieldInputType::dataListButtonElementWasClicked):
* Source/WebCore/html/shadow/SliderThumbElement.cpp:
(WebCore::RenderSliderContainer::computeLogicalHeight const):
* Source/WebCore/rendering/RenderTheme.cpp:
(WebCore::RenderTheme::hasListButton const):

Author: alice

Source/WebCore/accessibility/AccessibilityObject.cpp

@@ -3279,16 +3279,8 @@ String AccessibilityObject::popupValue() const
 
 bool AccessibilityObject::hasDatalist() const
 {
-    auto datalistId = getAttribute(listAttr);
-    if (datalistId.isEmpty())
-        return false;
-
-    auto element = this->element();
-    if (!element)
-        return false;
-
-    auto datalist = element->treeScope().getElementById(datalistId);
-    return is<HTMLDataListElement>(datalist);
+    RefPtr input = dynamicDowncast<HTMLInputElement>(element());
+    return input && input->hasDataList();
 }
 
 bool AccessibilityObject::supportsSetSize() const

Source/WebCore/html/HTMLInputElement.cpp

@@ -1888,6 +1888,11 @@ RefPtr<HTMLElement> HTMLInputElement::list() const
     return dataList();
 }
 
+bool HTMLInputElement::hasDataList() const
+{
+    return dataList();
+}
+
 RefPtr<HTMLDataListElement> HTMLInputElement::dataList() const
 {
     if (!m_hasNonEmptyList || !m_inputType->shouldRespectListAttribute())

Source/WebCore/html/HTMLInputElement.h

@@ -288,6 +288,7 @@ class HTMLInputElement final : public HTMLTextFormControlElement {
     bool willRespondToMouseClickEventsWithEditability(Editability) const final;
 
     WEBCORE_EXPORT bool isFocusingWithDataListDropdown() const;
+    bool hasDataList() const;
     RefPtr<HTMLDataListElement> dataList() const;
     void dataListMayHaveChanged();
 

Source/WebCore/html/TextFieldInputType.cpp

@@ -182,14 +182,14 @@ void TextFieldInputType::setValue(const String& sanitizedValue, bool valueChange
 
 void TextFieldInputType::handleClickEvent(MouseEvent&)
 {
-    if (element()->focused() && element()->list())
+    if (element()->focused() && element()->hasDataList())
         displaySuggestions(DataListSuggestionActivationType::ControlClicked);
 }
 
 void TextFieldInputType::showPicker()
 {
 #if !PLATFORM(IOS_FAMILY)
-    if (element()->list())
+    if (element()->hasDataList())
         displaySuggestions(DataListSuggestionActivationType::ControlClicked);
 #endif
 }
@@ -327,7 +327,7 @@ void TextFieldInputType::createShadowSubtree()
     bool shouldHaveSpinButton = this->shouldHaveSpinButton();
     bool shouldHaveCapsLockIndicator = this->shouldHaveCapsLockIndicator();
     bool shouldDrawAutoFillButton = this->shouldDrawAutoFillButton();
-    bool hasDataList = element()->list();
+    bool hasDataList = element()->hasDataList();
     bool createsContainer = shouldHaveSpinButton || shouldHaveCapsLockIndicator || shouldDrawAutoFillButton || hasDataList || needsContainer();
 
     Ref innerText = TextControlInnerTextElement::create(document, element()->isInnerTextElementEditable());
@@ -691,7 +691,7 @@ void TextFieldInputType::didSetValueByUserEdit()
         return;
     if (RefPtr frame = element()->document().frame())
         frame->editor().textDidChangeInTextField(*element());
-    if (element()->list())
+    if (element()->hasDataList())
         displaySuggestions(DataListSuggestionActivationType::TextChanged);
 }
 
@@ -884,7 +884,7 @@ void TextFieldInputType::dataListMayHaveChanged()
     if (!element())
         return;
     m_dataListDropdownIndicator->setInlineStyleProperty(CSSPropertyDisplay, element()->list() ? CSSValueBlock : CSSValueNone, IsImportant::Yes);
-    if (element()->list() && element()->focused())
+    if (element()->hasDataList() && element()->focused())
         displaySuggestions(DataListSuggestionActivationType::DataListMayHaveChanged);
 }
 
@@ -896,7 +896,7 @@ HTMLElement* TextFieldInputType::dataListButtonElement() const
 void TextFieldInputType::dataListButtonElementWasClicked()
 {
     Ref<HTMLInputElement> input(*element());
-    if (input->list()) {
+    if (input->hasDataList()) {
         m_isFocusingWithDataListDropdown = true;
         unsigned max = visibleValue().length();
         input->setSelectionRange(max, max);

Source/WebCore/html/shadow/SliderThumbElement.cpp

@@ -111,7 +111,7 @@ RenderBox::LogicalExtentComputedValues RenderSliderContainer::computeLogicalHeig
     auto& input = downcast<HTMLInputElement>(*element()->shadowHost());
     bool isVertical = hasVerticalAppearance(input);
 
-    if (input.renderer()->isRenderSlider() && !isVertical && input.list()) {
+    if (input.renderer()->isRenderSlider() && !isVertical && input.hasDataList()) {
         int offsetFromCenter = theme().sliderTickOffsetFromTrackCenter();
         LayoutUnit trackHeight;
         if (offsetFromCenter < 0)

Source/WebCore/rendering/RenderTheme.cpp

@@ -1224,7 +1224,7 @@ bool RenderTheme::isDefault(const RenderObject& o) const
 bool RenderTheme::hasListButton(const RenderObject& renderer) const
 {
     RefPtr input = dynamicDowncast<HTMLInputElement>(renderer.generatingNode());
-    return input && input->list();
+    return input && input->hasDataList();
 }
 
 bool RenderTheme::hasListButtonPressed(const RenderObject& renderer) const