Make Document.charset an alias of characterSet, as per spec

third_party/WebKit/Source/core/dom/ProcessingInstruction.cpp

 /*
  * Copyright (C) 2000 Peter Kelly (pmk@post.com)
  * Copyright (C) 2006, 2008, 2009 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 154 matching lines @@
     clearResource();
 
     String url = document().completeURL(href).string();
 
     ResourcePtr<StyleSheetResource> resource;
     FetchRequest request(ResourceRequest(document().completeURL(href)), FetchInitiatorTypeNames::processinginstruction);
     if (m_isXSL) {
         if (RuntimeEnabledFeatures::xsltEnabled())
             resource = XSLStyleSheetResource::fetch(request, document().fetcher());
     } else {
-        request.setCharset(charset.isEmpty() ? document().charset() : charset);
+        request.setCharset(charset.isEmpty() ? document().characterSet() : charset);
         resource = CSSStyleSheetResource::fetch(request, document().fetcher());
     }
 
     if (resource) {
         m_loading = true;
         if (!m_isXSL)
             document().styleEngine().addPendingSheet();
         setResource(resource);
     }
 }
@@ skipping 121 matching lines @@
 }
 
 DEFINE_TRACE(ProcessingInstruction)
 {
     visitor->trace(m_sheet);
     visitor->trace(m_listenerForXSLT);
     CharacterData::trace(visitor);
 }
 
 } // namespace