Dispatch change event for input type=checkbox when checked but value is null

Source/core/html/forms/RadioInputType.cpp

Index: Source/core/html/forms/RadioInputType.cpp
diff --git a/Source/core/html/forms/RadioInputType.cpp b/Source/core/html/forms/RadioInputType.cpp
index 7a90d2fad679dac692fdd4db8b4f66e48e19cef3..cc5a05ecd678ccabea009fba44730906fa74454a 100644
--- a/Source/core/html/forms/RadioInputType.cpp
+++ b/Source/core/html/forms/RadioInputType.cpp
@@ -191,4 +191,9 @@ bool RadioInputType::supportsIndeterminateAppearance() const
     return false;
 }
 
+bool RadioInputType::shouldDispatchFormControlChangeEvent(String& oldValue, String& newValue)
+{
+    return oldValue != newValue;
+}
+
 } // namespace WebCore