Non-activated default buttons prevent implicit form submission.

Source/core/html/HTMLButtonElement.cpp

Index: Source/core/html/HTMLButtonElement.cpp
diff --git a/Source/core/html/HTMLButtonElement.cpp b/Source/core/html/HTMLButtonElement.cpp
index cebae34c182e2ce6f3a8c329496e02f2130b737a..d70626f755fb1c3aeb840c789a9e76cb2ccdb039 100644
--- a/Source/core/html/HTMLButtonElement.cpp
+++ b/Source/core/html/HTMLButtonElement.cpp
@@ -159,11 +159,9 @@ bool HTMLButtonElement::willRespondToMouseClickEvents()
     return HTMLFormControlElement::willRespondToMouseClickEvents();
 }
 
-bool HTMLButtonElement::isSuccessfulSubmitButton() const
+bool HTMLButtonElement::canBeSuccessfulSubmitButton() const
 {
-    // HTML spec says that buttons must have names to be considered successful.
-    // However, other browsers do not impose this constraint.
-    return m_type == SUBMIT && !isDisabledFormControl();
+    return m_type == SUBMIT;
 }
 
 bool HTMLButtonElement::isActivatedSubmit() const