Add link preload as=document support

third_party/WebKit/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 376 matching lines @@
     InspectorInstrumentation::markResourceAsCached(frame(), identifier);
     if (!resource->response().isNull())
         dispatchDidReceiveResponseInternal(identifier, resource->response(), frameType, requestContext, resource, LinkLoader::DoNotLoadResources);
 
     if (resource->encodedSize() > 0)
         dispatchDidReceiveData(identifier, 0, resource->encodedSize(), 0);
 
     dispatchDidFinishLoading(identifier, 0, 0);
 }
 
-bool FrameFetchContext::shouldLoadNewResource(Resource::Type type) const
+bool FrameFetchContext::shouldLoadNewResource(Resource::Type type, const WebURLRequest::FrameType frameType) const
 {
     if (!m_documentLoader)
         return true;
-    if (type == Resource::MainResource)
+    if (type == Resource::MainResource && frameType != WebURLRequest::FrameTypePreload)
         return m_documentLoader == frame()->loader().provisionalDocumentLoader();
     return m_documentLoader == frame()->loader().documentLoader();
 }
 
 static std::unique_ptr<TracedValue> loadResourceTraceData(unsigned long identifier, const KURL& url, int priority)
 {
     String requestId = IdentifiersFactory::requestId(identifier);
 
     std::unique_ptr<TracedValue> value = TracedValue::create();
     value->setString("requestId", requestId);
@@ skipping 419 matching lines @@
 }
 
 DEFINE_TRACE(FrameFetchContext)
 {
     visitor->trace(m_document);
     visitor->trace(m_documentLoader);
     FetchContext::trace(visitor);
 }
 
 } // namespace blink