Use isHTML*Element() helpers more in the accessibility code

Source/core/accessibility/AXListBoxOption.cpp

Index: Source/core/accessibility/AXListBoxOption.cpp
diff --git a/Source/core/accessibility/AXListBoxOption.cpp b/Source/core/accessibility/AXListBoxOption.cpp
index 3708ccdab6792a24fd5c48330ba9a135a6c586ff..e8f82e75c5711379aea177184a9d48303a502bca 100644
--- a/Source/core/accessibility/AXListBoxOption.cpp
+++ b/Source/core/accessibility/AXListBoxOption.cpp
@@ -74,10 +74,7 @@ bool AXListBoxOption::isEnabled() const
 
 bool AXListBoxOption::isSelected() const
 {
-    if (!m_optionElement)
-        return false;
-
-    if (!m_optionElement->hasTagName(optionTag))
+    if (!isHTMLOptionElement(m_optionElement))
         return false;
 
     return toHTMLOptionElement(m_optionElement)->selected();
@@ -152,10 +149,10 @@ String AXListBoxOption::stringValue() const
     if (!ariaLabel.isNull())
         return ariaLabel;
 
-    if (m_optionElement->hasTagName(optionTag))
+    if (isHTMLOptionElement(*m_optionElement))
         return toHTMLOptionElement(m_optionElement)->text();
 
-    if (m_optionElement->hasTagName(optgroupTag))
+    if (isHTMLOptGroupElement(*m_optionElement))
         return toHTMLOptGroupElement(m_optionElement)->groupLabelText();
 
     return String();
@@ -198,10 +195,10 @@ HTMLSelectElement* AXListBoxOption::listBoxOptionParentNode() const
     if (!m_optionElement)
         return 0;
 
-    if (m_optionElement->hasTagName(optionTag))
+    if (isHTMLOptionElement(*m_optionElement))
         return toHTMLOptionElement(m_optionElement)->ownerSelectElement();
 
-    if (m_optionElement->hasTagName(optgroupTag))
+    if (isHTMLOptGroupElement(*m_optionElement))
         return toHTMLOptGroupElement(m_optionElement)->ownerSelectElement();
 
     return 0;