Non-activated default buttons prevent implicit form submission.

Source/core/html/HTMLInputElement.cpp

Index: Source/core/html/HTMLInputElement.cpp
diff --git a/Source/core/html/HTMLInputElement.cpp b/Source/core/html/HTMLInputElement.cpp
index 227a24a89c46a55ec995ca9b291820265aa578e7..0c3fe7407a7c202a3b0eb5f1c6c738e99a56a381 100644
--- a/Source/core/html/HTMLInputElement.cpp
+++ b/Source/core/html/HTMLInputElement.cpp
@@ -808,11 +808,9 @@ String HTMLInputElement::altText() const
     return alt;
 }
 
-bool HTMLInputElement::isSuccessfulSubmitButton() const
+bool HTMLInputElement::canBeSuccessfulSubmitButton() const
 {
-    // HTML spec says that buttons must have names to be considered successful.
-    // However, other browsers do not impose this constraint. So we do not.
-    return !isDisabledFormControl() && m_inputType->canBeSuccessfulSubmitButton();
+    return m_inputType->canBeSuccessfulSubmitButton();
 }
 
 bool HTMLInputElement::isActivatedSubmit() const