An unknown role is considered a bug, should never occur

third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

Index: third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp b/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
index eb389e086c2e0d601ae68e914321c49eadd939c2..06bfa6b6b2dd27a62597a95f94e528a3e4d973e2 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
@@ -685,17 +685,7 @@ AccessibilityRole AXNodeObject::DetermineAccessibilityRole() {
     return kStaticTextRole;
 
   AccessibilityRole role = NativeAccessibilityRoleIgnoringAria();
-  if (role != kUnknownRole)
-    return role;
-  if (GetNode()->IsElementNode()) {
-    Element* element = ToElement(GetNode());
-    // A generic element with tabIndex explicitly set gets GroupRole.
-    // The layout checks for focusability aren't critical here; a false
-    // positive would be harmless.
-    if (element->IsInCanvasSubtree() && element->SupportsFocus())
-      return kGenericContainerRole;
-  }
-  return kUnknownRole;
+  return role == kUnknownRole ? kGenericContainerRole : role;
 }
 
 AccessibilityRole AXNodeObject::DetermineAriaRoleAttribute() const {