Add handling to respect role attribute in AXObjects.

Source/modules/accessibility/AXSlider.cpp

Index: Source/modules/accessibility/AXSlider.cpp
diff --git a/Source/modules/accessibility/AXSlider.cpp b/Source/modules/accessibility/AXSlider.cpp
index d2c688ab7d8d3e755c232592f2eec516366433dc..c274248647d907c6d8d78ad3d883e18119f118b5 100644
--- a/Source/modules/accessibility/AXSlider.cpp
+++ b/Source/modules/accessibility/AXSlider.cpp
@@ -49,6 +49,14 @@ PassRefPtr<AXSlider> AXSlider::create(LayoutObject* layoutObject, AXObjectCacheI
     return adoptRef(new AXSlider(layoutObject, axObjectCache));
 }
 
+AccessibilityRole AXSlider::roleValue() const
+{
+    AccessibilityRole ariaRole = ariaRoleAttribute();
+    if (ariaRole != UnknownRole)
+        return ariaRole;
+    return SliderRole;
+}
+
 AccessibilityOrientation AXSlider::orientation() const
 {
     // Default to horizontal in the unknown case.