Remove resource type-specific fetching logic from ResourceFetcher

Source/core/loader/FrameFetchContext.cpp

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 555 matching lines @@
 {
     if (frame()->document())
         frame()->document()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, ErrorMessageLevel, message));
 }
 
 SecurityOrigin* FrameFetchContext::securityOrigin() const
 {
     return m_document ? m_document->securityOrigin() : nullptr;
 }
 
-String FrameFetchContext::charset() const
-{
-    return m_document ? m_document->charset().string() : String();
-}
-
 void FrameFetchContext::upgradeInsecureRequest(FetchRequest& fetchRequest)
 {
     if (!m_document)
         return;
 
     KURL url = fetchRequest.resourceRequest().url();
 
     // Tack an 'HTTPS' header to outgoing navigational requests, as described in
     // https://w3c.github.io/webappsec/specs/upgrade/#feature-detect
     if (fetchRequest.resourceRequest().frameType() != WebURLRequest::FrameTypeNone)
@@ skipping 50 matching lines @@
         fetchRequest.mutableResourceRequest().addHTTPHeaderField("CSP", "active");
 }
 
 DEFINE_TRACE(FrameFetchContext)
 {
     visitor->trace(m_document);
     FetchContext::trace(visitor);
 }
 
 } // namespace blink