submit() in submit event handler should not contains a value of a submit button.

third_party/WebKit/Source/core/html/HTMLButtonElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 96 matching lines @@
         if (name == formactionAttr)
             logUpdateAttributeIfIsolatedWorldAndInDocument("button", formactionAttr, oldValue, value);
         HTMLFormControlElement::parseAttribute(name, oldValue, value);
     }
 }
 
 void HTMLButtonElement::defaultEventHandler(Event* event)
 {
     if (event->type() == EventTypeNames::DOMActivate && !isDisabledFormControl()) {
         if (form() && m_type == SUBMIT) {
-            m_isActivatedSubmit = true;
-            form()->prepareForSubmission(event);
+            form()->prepareForSubmission(event, this);
             event->setDefaultHandled();
-            m_isActivatedSubmit = false; // Do this in case submission was canceled.
         }
         if (form() && m_type == RESET) {
             form()->reset();
             event->setDefaultHandled();
         }
     }
 
     if (event->isKeyboardEvent()) {
         if (event->type() == EventTypeNames::keydown && toKeyboardEvent(event)->key() == " ") {
             setActive(true);
@@ skipping 91 matching lines @@
 }
 
 Node::InsertionNotificationRequest HTMLButtonElement::insertedInto(ContainerNode* insertionPoint)
 {
     InsertionNotificationRequest request = HTMLFormControlElement::insertedInto(insertionPoint);
     logAddElementIfIsolatedWorldAndInDocument("button", typeAttr, formmethodAttr, formactionAttr);
     return request;
 }
 
 } // namespace blink