Form validation: Validation bubble should be closed on document unload process.

third_party/WebKit/Source/core/html/HTMLFormControlElement.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 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 443 matching lines @@
     TextDirection& messageDir,
     String& subMessage,
     TextDirection& subMessageDir) {
   messageDir = determineDirectionality(message);
   if (!subMessage.isEmpty())
     subMessageDir = layoutObject()->style()->direction();
 }
 
 void HTMLFormControlElement::updateVisibleValidationMessage() {
   Page* page = document().page();
-  if (!page || !page->isPageVisible())
+  if (!page || !page->isPageVisible() || document().unloadStarted())
     return;
   String message;
   if (layoutObject() && willValidate())
     message = validationMessage().stripWhiteSpace();
 
   m_hasValidationMessage = true;
   ValidationMessageClient* client = &page->validationMessageClient();
   TextDirection messageDir = TextDirection::kLtr;
   TextDirection subMessageDir = TextDirection::kLtr;
   String subMessage = validationSubMessage().stripWhiteSpace();
@@ skipping 160 matching lines @@
     const Element& source) {
   HTMLElement::copyNonAttributePropertiesFromElement(source);
   setNeedsValidityCheck();
 }
 
 void HTMLFormControlElement::associateWith(HTMLFormElement* form) {
   associateByParser(form);
 };
 
 }  // namespace blink