Implement select listbox using shadow DOM

Source/core/html/HTMLSelectElement.cpp

Index: Source/core/html/HTMLSelectElement.cpp
diff --git a/Source/core/html/HTMLSelectElement.cpp b/Source/core/html/HTMLSelectElement.cpp
index b0dc747ff14ab9cee6caa8a9264b2d0c2834ad1f..6c73522ea1ef631a2f930f8c55bb24865a1119a2 100644
--- a/Source/core/html/HTMLSelectElement.cpp
+++ b/Source/core/html/HTMLSelectElement.cpp
@@ -39,16 +39,23 @@
 #include "core/events/GestureEvent.h"
 #include "core/events/KeyboardEvent.h"
 #include "core/events/MouseEvent.h"
+#include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/FormDataList.h"
 #include "core/html/HTMLFormElement.h"
+#include "core/html/HTMLOptGroupElement.h"
 #include "core/html/HTMLOptionElement.h"
 #include "core/html/forms/FormController.h"
+#include "core/page/AutoscrollController.h"
 #include "core/page/EventHandler.h"
+#include "core/page/Page.h"
 #include "core/page/SpatialNavigation.h"
+#include "core/rendering/HitTestRequest.h"
+#include "core/rendering/HitTestResult.h"
 #include "core/rendering/RenderListBox.h"
 #include "core/rendering/RenderMenuList.h"
 #include "core/rendering/RenderTheme.h"
+#include "core/rendering/RenderView.h"
 #include "platform/PlatformMouseEvent.h"
 #include "platform/text/PlatformLocale.h"
 
@@ -73,6 +80,7 @@ HTMLSelectElement::HTMLSelectElement(Document& document, HTMLFormElement* form)
     , m_activeSelectionState(false)
     , m_shouldRecalcListItems(false)
     , m_suggestedIndex(-1)
+    , m_capturing(false)
 {
     ScriptWrappable::init(this);
     setHasCustomStyleCallbacks();
@@ -334,9 +342,11 @@ void HTMLSelectElement::parseAttribute(const QualifiedName& name, const AtomicSt
 
         m_size = size;
         setNeedsValidityCheck();
-        if (m_size != oldSize && inActiveDocument()) {
-            lazyReattachIfAttached();
-            setRecalcListItems();
+        if (m_size != oldSize && document().isActive()) {
+            // ensureShadowDOM needs to be run even when !inDocument().
+            updateView();
+            if (inDocument())
+                setRecalcListItems();
         }
     } else if (name == multipleAttr)
         parseMultipleAttribute(value);
@@ -366,7 +376,7 @@ bool HTMLSelectElement::canSelectAll() const
     return !usesMenuList();
 }
 
-RenderObject* HTMLSelectElement::createRenderer(RenderStyle*)
+RenderObject* HTMLSelectElement::createRenderer(RenderStyle* style)
 {
     if (usesMenuList())
         return new RenderMenuList(this);
@@ -703,11 +713,13 @@ void HTMLSelectElement::dispatchInputAndChangeEventForMenuList(bool requiresUser
 
 void HTMLSelectElement::scrollToSelection()
 {
+    if (!isFinishedParsingChildren())

[keishi, 2014/06/22 11:59:55]

scrollToSelection is very slow compared to the current implementation because we
use element.scrollIntoViewIfNecessary which does layout.
menulist-appearance-basic.html timesout unless we do this.

+        return;
     if (usesMenuList())
         return;
-
-    if (RenderObject* renderer = this->renderer())
-        toRenderListBox(renderer)->selectionChanged();
+    scrollTo(activeSelectionEndListIndex());
+    if (AXObjectCache* cache = document().existingAXObjectCache())
+        cache->selectedChildrenChanged(this);
 }
 
 void HTMLSelectElement::setOptionsChangedOnRenderer()
@@ -715,8 +727,6 @@ void HTMLSelectElement::setOptionsChangedOnRenderer()
     if (RenderObject* renderer = this->renderer()) {
         if (usesMenuList())
             toRenderMenuList(renderer)->setOptionsChanged(true);
-        else
-            toRenderListBox(renderer)->setOptionsChanged(true);
     }
 }
 
@@ -858,11 +868,21 @@ void HTMLSelectElement::setSuggestedIndex(int suggestedIndex)
 
     if (RenderObject* renderer = this->renderer())  {
         renderer->updateFromElement();
-        if (renderer->isListBox())
-            toRenderListBox(renderer)->scrollToRevealElementAtListIndex(suggestedIndex);
+        scrollTo(suggestedIndex);
     }
 }
 
+void HTMLSelectElement::scrollTo(int listIndex)
+{
+    if (listIndex < 0)
+        return;
+    const WillBeHeapVector<RawPtrWillBeMember<HTMLElement> >& items = listItems();
+    int listSize = static_cast<int>(items.size());
+    if (listIndex >= listSize)
+        return;
+    items[listIndex]->scrollIntoViewIfNeeded(false);
+}
+
 void HTMLSelectElement::optionSelectionStateChanged(HTMLOptionElement* option, bool optionIsSelected)
 {
     ASSERT(option->ownerSelectElement() == this);
@@ -874,6 +894,15 @@ void HTMLSelectElement::optionSelectionStateChanged(HTMLOptionElement* option, b
         selectOption(nextSelectableListIndex(-1));
 }
 
+void HTMLSelectElement::optionRemoved(HTMLOptionElement* option)

[keishi, 2014/06/22 11:59:56]

listbox-clear-restore.html tests that the scroll position will not be preserved
when removing all options and adding them back.
Right now RenderListBox::layout is resetting the scroll position to zero when
all options are removed.
That is a hack. What we should be doing is adjust the active selection when
options are removed.

+{
+    int listIndex = optionToListIndex(option->index());
+    if (listIndex <= m_activeSelectionAnchorIndex)
+        m_activeSelectionAnchorIndex--;
+    if (listIndex <= m_activeSelectionEndIndex)
+        m_activeSelectionEndIndex--;
+}
+
 void HTMLSelectElement::selectOption(int optionIndex, SelectOptionFlags flags)
 {
     bool shouldDeselect = !m_multiple || (flags & DeselectOtherOptions);
@@ -909,10 +938,12 @@ void HTMLSelectElement::selectOption(int optionIndex, SelectOptionFlags flags)
         if (flags & DispatchInputAndChangeEvent)
             dispatchInputAndChangeEventForMenuList();
         if (RenderObject* renderer = this->renderer()) {
-            if (usesMenuList())
+            if (usesMenuList()) {
                 toRenderMenuList(renderer)->didSetSelectedIndex(listIndex);
-            else if (renderer->isListBox())
-                toRenderListBox(renderer)->selectionChanged();
+            } else if (renderer->isListBox()) {
+                if (AXObjectCache* cache = document().existingAXObjectCache())
+                    cache->selectedChildrenChanged(this);
+            }
         }
     }
 
@@ -1053,11 +1084,27 @@ void HTMLSelectElement::restoreFormControlState(const FormControlState& state)
 
 void HTMLSelectElement::parseMultipleAttribute(const AtomicString& value)
 {
-    bool oldUsesMenuList = usesMenuList();
     m_multiple = !value.isNull();
     setNeedsValidityCheck();
-    if (oldUsesMenuList != usesMenuList())
-        lazyReattachIfAttached();
+
+    updateView();
+}
+
+void HTMLSelectElement::updateView()
+{
+    if (!usesMenuList())
+        ensureUserAgentShadowRoot();
+    else if (userAgentShadowRoot())
+        userAgentShadowRoot()->detach();
+    const WillBeHeapVector<RawPtrWillBeMember<HTMLElement> >& items = listItems();
+    for (unsigned i = 0; i < items.size(); ++i) {
+        HTMLElement* element = items[i];
+        if (isHTMLOptionElement(*element))
+            toHTMLOptionElement(*element).updateView();
+        else if (isHTMLOptGroupElement(*element))
+            toHTMLOptGroupElement(*element).updateView();
+    }
+    lazyReattachIfAttached();
 }
 
 bool HTMLSelectElement::appendFormData(FormDataList& list, bool)
@@ -1335,6 +1382,51 @@ void HTMLSelectElement::updateSelectedState(int listIndex, bool multi, bool shif
     updateListBoxSelection(!multiSelect);
 }
 
+int HTMLSelectElement::listIndexForMouseEvent(const MouseEvent& event)
+{
+    Node* targetNode = event.target()->toNode();
+    if (targetNode != this)
+        return listIndexForEvent(event);
+    HitTestRequest request(HitTestRequest::ReadOnly | HitTestRequest::Active | HitTestRequest::Move | HitTestRequest::ConfusingAndOftenMisusedDisallowShadowContent);
+    HitTestResult result(event.absoluteLocation());
+    document().renderView()->hitTest(request, result);
+    Node* hitNode = result.targetNode();
+    if (!hitNode)
+        return -1;
+    return listIndexForNode(*hitNode);
+}
+
+int HTMLSelectElement::listIndexForEvent(const Event& event)
+{
+    Node* targetNode = event.target()->toNode();
+    if (!targetNode)
+        return -1;
+    return listIndexForNode(*targetNode);
+}
+
+int HTMLSelectElement::listIndexForNode(const Node& targetNode)
+{
+    const WillBeHeapVector<RawPtrWillBeMember<HTMLElement> >& items = this->listItems();
+    for (const Node* node = &targetNode; node; node = node->parentOrShadowHostNode()) {
+        if (node->isElementNode() && (toElement(node)->hasTagName(optionTag) || toElement(node)->hasTagName(optgroupTag))) {
+            size_t length = items.size();
+            for (size_t i = 0; i < length; ++i) {
+                if (items[i] == node) {
+                    return i;
+                }
+            }
+        }
+    }
+    return -1;
+}
+
+AutoscrollController* HTMLSelectElement::autoscrollController() const
+{
+    if (Page* page = document().page())
+        return &page->autoscrollController();
+    return 0;
+}
+
 void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
 {
     const WillBeHeapVector<RawPtrWillBeMember<HTMLElement> >& listItems = this->listItems();
@@ -1346,8 +1438,7 @@ void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
 
         // Convert to coords relative to the list box if needed.
         GestureEvent& gestureEvent = toGestureEvent(*event);
-        IntPoint localOffset = roundedIntPoint(renderer()->absoluteToLocal(gestureEvent.absoluteLocation(), UseTransforms));
-        int listIndex = toRenderListBox(renderer())->listIndexAtOffset(toIntSize(localOffset));
+        int listIndex = listIndexForEvent(gestureEvent);
         if (listIndex >= 0) {
             if (!isDisabledFormControl())
                 updateSelectedState(listIndex, true, gestureEvent.shiftKey());
@@ -1359,10 +1450,17 @@ void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
         if (!renderer() || !renderer()->isListBox() || isDisabledFormControl())
             return;
 
+        if (Page* page = document().page())
+            page->autoscrollController().startAutoscrollForSelection(renderer());
+
+        if (LocalFrame* frame = document().frame()) {
+            frame->eventHandler().setCapturingMouseEventsNode(this);
+            m_capturing = true;
+        }
+
         // Convert to coords relative to the list box if needed.
         MouseEvent* mouseEvent = toMouseEvent(event);
-        IntPoint localOffset = roundedIntPoint(renderer()->absoluteToLocal(mouseEvent->absoluteLocation(), UseTransforms));
-        int listIndex = toRenderListBox(renderer())->listIndexAtOffset(toIntSize(localOffset));
+        int listIndex = listIndexForMouseEvent(*mouseEvent);
         if (listIndex >= 0) {
             if (!isDisabledFormControl()) {
 #if OS(MACOSX)
@@ -1376,13 +1474,11 @@ void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
 
             event->setDefaultHandled();
         }
-    } else if (event->type() == EventTypeNames::mousemove && event->isMouseEvent() && !toRenderBox(renderer())->canBeScrolledAndHasScrollableArea()) {
+    } else if (event->type() == EventTypeNames::mousemove && event->isMouseEvent()) {
         MouseEvent* mouseEvent = toMouseEvent(event);
         if (mouseEvent->button() != LeftButton || !mouseEvent->buttonDown())
             return;
-
-        IntPoint localOffset = roundedIntPoint(renderer()->absoluteToLocal(mouseEvent->absoluteLocation(), UseTransforms));
-        int listIndex = toRenderListBox(renderer())->listIndexAtOffset(toIntSize(localOffset));
+        int listIndex = listIndexForMouseEvent(*mouseEvent);
         if (listIndex >= 0) {
             if (!isDisabledFormControl()) {
                 if (m_multiple) {
@@ -1399,7 +1495,12 @@ void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
                 }
             }
         }
-    } else if (event->type() == EventTypeNames::mouseup && event->isMouseEvent() && toMouseEvent(event)->button() == LeftButton && renderer() && !toRenderBox(renderer())->autoscrollInProgress()) {
+    } else if (event->type() == EventTypeNames::mouseup && event->isMouseEvent() && toMouseEvent(event)->button() == LeftButton && renderer()) {
+        LocalFrame* frame = document().frame();
+        if (m_capturing && frame) {
+            frame->eventHandler().setCapturingMouseEventsNode(nullptr);
+            m_capturing = false;
+        }
         // We didn't start this click/drag on any options.
         if (m_lastOnChangeSelection.isEmpty())
             return;
@@ -1478,7 +1579,7 @@ void HTMLSelectElement::listBoxDefaultEventHandler(Event* event)
                 setActiveSelectionAnchorIndex(m_activeSelectionEndIndex);
             }
 
-            toRenderListBox(renderer())->scrollToRevealElementAtListIndex(endIndex);
+            scrollTo(endIndex);
             if (selectNewItem) {
                 updateListBoxSelection(deselectOthers);
                 listBoxOnChange();
@@ -1629,6 +1730,7 @@ void HTMLSelectElement::finishParsingChildren()
 {
     HTMLFormControlElementWithState::finishParsingChildren();
     updateListItemSelectedStates();
+    scrollToSelection();
 }
 
 bool HTMLSelectElement::anonymousIndexedSetter(unsigned index, PassRefPtrWillBeRawPtr<HTMLOptionElement> value, ExceptionState& exceptionState)
@@ -1664,4 +1766,11 @@ void HTMLSelectElement::trace(Visitor* visitor)
     HTMLFormControlElementWithState::trace(visitor);
 }
 
+void HTMLSelectElement::didAddUserAgentShadowRoot(ShadowRoot& root)
+{
+    RefPtrWillBeRawPtr<HTMLContentElement> content = HTMLContentElement::create(document());
+    content->setAttribute(selectAttr, "option,optgroup");
+    root.appendChild(content);
+}
+
 } // namespace