Don't include headers from the layout API from other headers needlessly.

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
  * License as published by the Free Software Foundation; either
@@ skipping 30 matching lines @@
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/html/HTMLCollection.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFormControlsCollection.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLObjectElement.h"
 #include "core/html/RadioNodeList.h"
 #include "core/html/forms/FormController.h"
 #include "core/inspector/ConsoleMessage.h"
+#include "core/layout/LayoutObject.h"
 #include "core/loader/FormSubmission.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/loader/MixedContentChecker.h"
 #include "core/loader/NavigationScheduler.h"
 #include "platform/UserGestureIndicator.h"
 #include "public/platform/WebInsecureRequestPolicy.h"
 #include "wtf/AutoReset.h"
 #include "wtf/text/AtomicString.h"
 #include <limits>
@@ skipping 738 matching lines @@
 {
     for (const auto& control : associatedElements()) {
         if (!control->isFormControlElement())
             continue;
         if (toHTMLFormControlElement(control)->canBeSuccessfulSubmitButton())
             toHTMLFormControlElement(control)->pseudoStateChanged(CSSSelector::PseudoDefault);
     }
 }
 
 } // namespace blink