Fixed the behaviour of form submit to match the standard: no submit is taken place when the form is…

third_party/WebKit/Source/core/html/HTMLFormElement.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, 2008, 2009 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
@@ skipping 329 matching lines @@
   }
 }
 
 void HTMLFormElement::submit(Event* event,
                              HTMLFormControlElement* submitButton) {
   FrameView* view = document().view();
   LocalFrame* frame = document().frame();
   if (!view || !frame || !frame->page())
     return;
 
-  // See crbug.com/586749.
-  if (!isConnected())
-    UseCounter::count(document(), UseCounter::FormSubmissionNotInDocumentTree);
+  // https://html.spec.whatwg.org/multipage/forms.html#form-submission-algorithm
+  // 2. If form document is not connected, has no associated browsing context,
+  // or its active sandboxing flag set has its sandboxed forms browsing
+  // context flag set, then abort these steps without doing anything.
+  if (!isConnected()) {
+    document().addConsoleMessage(ConsoleMessage::create(
+        JSMessageSource, WarningMessageLevel,
+        "Form submission canceled because the form is not connected"));
+    return;
+  }
 
   if (m_isSubmitting)
     return;
 
   // Delay dispatching 'close' to dialog until done submitting.
   EventQueueScope scopeForDialogClose;
   AutoReset<bool> submitScope(&m_isSubmitting, true);
 
   if (event && !submitButton) {
     // In a case of implicit submission without a submit button, 'submit'
@@ skipping 443 matching lines @@
   for (const auto& control : associatedElements()) {
     if (!control->isFormControlElement())
       continue;
     if (toHTMLFormControlElement(control)->canBeSuccessfulSubmitButton())
       toHTMLFormControlElement(control)->pseudoStateChanged(
           CSSSelector::PseudoDefault);
   }
 }
 
 }  // namespace blink