Move DragCaretController class to its own file

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 87 matching lines @@
 #include "core/dom/TouchList.h"
 #include "core/dom/TransformSource.h"
 #include "core/dom/TreeWalker.h"
 #include "core/dom/VisitedLinkState.h"
 #include "core/dom/XMLDocument.h"
 #include "core/dom/custom/CustomElementMicrotaskRunQueue.h"
 #include "core/dom/custom/CustomElementRegistrationContext.h"
 #include "core/dom/shadow/ComposedTreeTraversal.h"
 #include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/ShadowRoot.h"
+#include "core/editing/DragCaretController.h"
 #include "core/editing/Editor.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/SpellChecker.h"
 #include "core/editing/markup.h"
 #include "core/events/BeforeUnloadEvent.h"
 #include "core/events/Event.h"
 #include "core/events/EventFactory.h"
 #include "core/events/EventListener.h"
 #include "core/events/HashChangeEvent.h"
 #include "core/events/PageTransitionEvent.h"
@@ skipping 5690 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     WeakDocumentSet& set = liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif