Enable `as` based priorities for <link rel=preload>

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 339 matching lines @@
     // any URL.
     switch (type) {
     case Resource::MainResource:
     case Resource::Image:
     case Resource::CSSStyleSheet:
     case Resource::Script:
     case Resource::Font:
     case Resource::Raw:
     case Resource::LinkPrefetch:
     case Resource::LinkSubresource:
+    case Resource::LinkPreload:
     case Resource::TextTrack:
     case Resource::ImportResource:
     case Resource::Media:
         // By default these types of resources can be loaded from any origin.
         // FIXME: Are we sure about Resource::Font?
         if (originRestriction == FetchRequest::RestrictToSameOrigin && !securityOrigin->canRequest(url)) {
             printAccessDeniedMessage(url);
             return false;
         }
         break;
@@ skipping 58 matching lines @@
     case Resource::Font: {
         ASSERT(ContentSecurityPolicy::isFontResource(resourceRequest));
         if (!shouldBypassMainWorldCSP && !csp->allowFontFromSource(url, redirectStatus, cspReporting))
             return false;
         break;
     }
     case Resource::MainResource:
     case Resource::Raw:
     case Resource::LinkPrefetch:
     case Resource::LinkSubresource:
+    case Resource::LinkPreload:
         break;
     case Resource::Media:
     case Resource::TextTrack:
         ASSERT(ContentSecurityPolicy::isMediaResource(resourceRequest));
         if (!shouldBypassMainWorldCSP && !csp->allowMediaFromSource(url, redirectStatus, cspReporting))
             return false;
 
         if (!frame()->loader().client()->allowMedia(url))
             return false;
         break;
@@ skipping 191 matching lines @@
         fetchRequest.mutableResourceRequest().addHTTPHeaderField("CSP", "active");
 }
 
 DEFINE_TRACE(FrameFetchContext)
 {
     visitor->trace(m_document);
     FetchContext::trace(visitor);
 }
 
 } // namespace blink