Add isTabStop attribute to Element

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 0308c86a5a355803496dc8aa5c298f7c7fcef8b5..de71ef60a97a71d80c5c03c445746d0e56d5e148 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -149,6 +149,7 @@ PassRefPtrWillBeRawPtr<Element> Element::create(const QualifiedName& tagName, Do
 Element::Element(const QualifiedName& tagName, Document* document, ConstructionType type)
     : ContainerNode(document, type)
     , m_tagName(tagName)
+    , m_isTabStop(true)
 {
 }
 
@@ -217,6 +218,8 @@ void Element::clearTabIndexExplicitlyIfNeeded()
 void Element::setTabIndexExplicitly(short tabIndex)
 {
     ensureElementRareData().setTabIndexExplicitly(tabIndex);
+    // isTabStop is overridden by setting tabindex.
+    m_isTabStop = (tabIndex >= 0);
 }
 
 void Element::setTabIndex(int value)
@@ -2250,6 +2253,17 @@ bool Element::isMouseFocusable() const
     return isFocusable();
 }
 
+bool Element::isTabStop() const
+{
+    // Any element which never supports focus will always return false.
+    return supportsFocus() ? m_isTabStop : false;

[vivekg, 2015/02/13 10:28:36]

nit: return supportsFocus() && m_isTabStop;

[kochi, 2015/02/19 06:10:47]

Done.

+}
+
+void Element::setIsTabStop(bool flag)
+{
+    m_isTabStop = flag;
+}
+
 void Element::dispatchFocusEvent(Element* oldFocusedElement, WebFocusType type)
 {
     RefPtrWillBeRawPtr<FocusEvent> event = FocusEvent::create(EventTypeNames::focus, false, false, document().domWindow(), 0, oldFocusedElement);