[WIP] Implement :dir()

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

Index: third_party/WebKit/Source/core/html/HTMLElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLElement.cpp b/third_party/WebKit/Source/core/html/HTMLElement.cpp
index 6315b9278f5133ba3187559df498d20f6070aa9b..2c76cff5df404c7a92c92fd22f562eb830706229 100644
--- a/third_party/WebKit/Source/core/html/HTMLElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLElement.cpp
@@ -711,15 +711,7 @@ bool HTMLElement::hasDirectionAuto() const
     return (isHTMLBDIElement(*this) && direction == nullAtom) || equalIgnoringCase(direction, "auto");
 }
 
-TextDirection HTMLElement::directionalityIfhasDirAutoAttribute(bool& isAuto) const
-{
-    isAuto = hasDirectionAuto();
-    if (!isAuto)
-        return LTR;
-    return directionality();
-}
-
-TextDirection HTMLElement::directionality(Node** strongDirectionalityTextNode) const
+TextDirection HTMLElement::computeDirectionality(Node** strongDirectionalityTextNode) const
 {
     if (isHTMLInputElement(*this)) {
         HTMLInputElement* inputElement = toHTMLInputElement(const_cast<HTMLElement*>(this));
@@ -776,32 +768,46 @@ void HTMLElement::dirAttributeChanged(const AtomicString& value)
     updateDistribution();
     Element* parent = FlatTreeTraversal::parentElement(*this);
     if (parent && parent->isHTMLElement() && toHTMLElement(parent)->selfOrAncestorHasDirAutoAttribute())
-        toHTMLElement(parent)->adjustDirectionalityIfNeededAfterChildAttributeChanged(this);
+        toHTMLElement(parent)->updateSelfOrAncestorForDirAuto();
 
-    if (equalIgnoringCase(value, "auto"))
-        calculateAndAdjustDirectionality();
+    if (equalIgnoringCase(value, "auto")) {
+        updateForDirAuto();
+    } else if (elementData() && elementData()->directionality() != CachedTextDirection::NotAutoOrNotCached) {
+        DCHECK(elementData()->isUnique());
+        const_cast<ElementData*>(elementData())->setDirectionality(CachedTextDirection::NotAutoOrNotCached);
+    }
 }
 
-void HTMLElement::adjustDirectionalityIfNeededAfterChildAttributeChanged(Element* child)
+void HTMLElement::updateSelfOrAncestorForDirAuto()
 {
     ASSERT(selfOrAncestorHasDirAutoAttribute());
-    TextDirection textDirection = directionality();
-    if (layoutObject() && layoutObject()->style() && layoutObject()->style()->direction() != textDirection) {
-        Element* elementToAdjust = this;
-        for (; elementToAdjust; elementToAdjust = FlatTreeTraversal::parentElement(*elementToAdjust)) {
-            if (elementAffectsDirectionality(elementToAdjust)) {
-                elementToAdjust->setNeedsStyleRecalc(LocalStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::WritingModeChange));
-                return;
-            }
-        }
-    }
+    //XXX add test that this would code would fail
+    //TextDirection textDirection = computeDirectionality();
+    //if (layoutObject() && layoutObject()->style() && layoutObject()->style()->direction() != textDirection) {
+    Element* elementToAdjust = this;
+    while (!elementAffectsDirectionality(elementToAdjust))
+        elementToAdjust = FlatTreeTraversal::parentElement(*elementToAdjust);
+    toHTMLElement(elementToAdjust)->updateForDirAuto();
+}
+
+void HTMLElement::updateForDirAuto()
+{
+    if (!hasDirectionAuto())
+        return;
+    ensureUniqueElementData().setDirectionality(CachedTextDirection::NotAutoOrNotCached);
+    pseudoStateChanged(CSSSelector::PseudoDir);
+    setNeedsStyleRecalc(LocalStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::WritingModeChange));
 }
 
-void HTMLElement::calculateAndAdjustDirectionality()
+void HTMLElement::cacheDirectionalityForDirAuto() const
 {
-    TextDirection textDirection = directionality();
-    if (layoutObject() && layoutObject()->style() && layoutObject()->style()->direction() != textDirection)
-        setNeedsStyleRecalc(LocalStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::WritingModeChange));
+    DCHECK(hasDirectionAuto());
+    DCHECK(elementData() && elementData()->isUnique());
+    DCHECK(elementData()->directionality() == CachedTextDirection::NotAutoOrNotCached);
+    if (computeDirectionality() == LTR)
+        elementData()->setDirectionality(CachedTextDirection::AutoLTR);
+    else
+        elementData()->setDirectionality(CachedTextDirection::AutoRTL);
 }
 
 void HTMLElement::adjustDirectionalityIfNeededAfterChildrenChanged(const ChildrenChange& change)
@@ -810,13 +816,7 @@ void HTMLElement::adjustDirectionalityIfNeededAfterChildrenChanged(const Childre
         return;
 
     updateDistribution();
-
-    for (Element* elementToAdjust = this; elementToAdjust; elementToAdjust = FlatTreeTraversal::parentElement(*elementToAdjust)) {
-        if (elementAffectsDirectionality(elementToAdjust)) {
-            toHTMLElement(elementToAdjust)->calculateAndAdjustDirectionality();
-            return;
-        }
-    }
+    updateSelfOrAncestorForDirAuto();
 }
 
 void HTMLElement::addHTMLLengthToStyle(MutableStylePropertySet* style, CSSPropertyID propertyID, const String& value)