Remove resource type-specific fetching logic from ResourceFetcher

Source/core/loader/DocumentLoader.cpp

Index: Source/core/loader/DocumentLoader.cpp
diff --git a/Source/core/loader/DocumentLoader.cpp b/Source/core/loader/DocumentLoader.cpp
index d80bd429baa7451381f37619dd4842c2e7ad9369..040bc1375bdbd339d59c5ff338410dd31adf51b3 100644
--- a/Source/core/loader/DocumentLoader.cpp
+++ b/Source/core/loader/DocumentLoader.cpp
@@ -690,7 +690,7 @@ void DocumentLoader::startLoadingMainResource()
     DEFINE_STATIC_LOCAL(ResourceLoaderOptions, mainResourceLoadOptions,
         (DoNotBufferData, AllowStoredCredentials, ClientRequestedCredentials, CheckContentSecurityPolicy, DocumentContext));
     FetchRequest cachedResourceRequest(request, FetchInitiatorTypeNames::document, mainResourceLoadOptions);
-    m_mainResource = m_fetcher->fetchMainResource(cachedResourceRequest, m_substituteData);
+    m_mainResource = RawResource::fetchMainResource(cachedResourceRequest, fetcher(), m_substituteData);
     if (!m_mainResource) {
         m_request = ResourceRequest();
         // If the load was aborted by clearing m_request, it's possible the ApplicationCacheHost