Have Document::markers() return a reference

Source/web/SpellCheckerClientImpl.cpp

 /*
  * Copyright (C) 2006, 2007 Apple, Inc.  All rights reserved.
  * Copyright (C) 2012 Google, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 77 matching lines @@
         return true;
     return shouldSpellcheckByDefault();
 }
 
 void SpellCheckerClientImpl::toggleContinuousSpellChecking()
 {
     if (isContinuousSpellCheckingEnabled()) {
         m_spellCheckThisFieldStatus = SpellCheckForcedOff;
         if (Page* page = m_webView->page()) {
             for (LocalFrame* frame = page->mainFrame(); frame && frame->document(); frame = frame->tree().traverseNext()) {
-                frame->document()->markers()->removeMarkers(DocumentMarker::MisspellingMarkers());
+                frame->document()->markers().removeMarkers(DocumentMarker::MisspellingMarkers());
             }
         }
     } else {
         m_spellCheckThisFieldStatus = SpellCheckForcedOn;
         if (LocalFrame* frame = m_webView->focusedWebCoreFrame()) {
             VisibleSelection frameSelection = frame->selection().selection();
             // If a selection is in an editable element spell check its content.
             if (Element* rootEditableElement = frameSelection.rootEditableElement()) {
                 frame->spellChecker().didBeginEditing(rootEditableElement);
             }
@@ skipping 111 matching lines @@
 }
 
 bool SpellCheckerClientImpl::spellingUIIsShowing()
 {
     if (m_webView->spellCheckClient())
         return m_webView->spellCheckClient()->isShowingSpellingUI();
     return false;
 }
 
 } // namesace WebKit