Make ResourceFetcher return Resources with LoadError instead of nullptrs.

third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     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
@@ skipping 357 matching lines @@
     resource->setIdentifier(createUniqueIdentifier());
     resource->setCacheIdentifier(cacheIdentifier);
     resource->finish();
 
     if (!substituteData.isValid())
         memoryCache()->add(resource);
 
     return resource;
 }
 
+Resource* ResourceFetcher::resourceForBlockedRequest(const FetchRequest& request, const ResourceFactory& factory)
+{
+    Resource* resource = factory.create(request.resourceRequest(), request.options(), request.charset());
+    resource->error(ResourceError::cancelledDueToAccessCheckError(request.url()));
+    return resource;
+}
+
 void ResourceFetcher::moveCachedNonBlockingResourceToBlocking(Resource* resource, const FetchRequest& request)
 {
     // TODO(yoav): Test that non-blocking resources (video/audio/track) continue to not-block even after being preloaded and discovered.
     if (resource && resource->loader() && resource->isLoadEventBlockingResourceType() && resource->isLinkPreload() && !request.forPreload()) {
         m_nonBlockingLoaders.remove(resource->loader());
         m_loaders.add(resource->loader());
     }
 }
 
 void ResourceFetcher::updateMemoryCacheStats(Resource* resource, RevalidationPolicy policy, const FetchRequest& request,  const ResourceFactory& factory, bool isStaticData) const
@@ skipping 24 matching lines @@
     if (request.resourceRequest().httpHeaderField("Upgrade-Insecure-Requests") != AtomicString("1"))
         context().upgradeInsecureRequest(request.mutableResourceRequest());
     context().addClientHintsIfNecessary(request);
     context().addCSPHeaderIfNecessary(factory.type(), request);
 
     TRACE_EVENT1("blink", "ResourceFetcher::requestResource", "url", urlForTraceEvent(request.url()));
 
     if (!request.url().isValid())
         return nullptr;
 
-    if (!context().canRequest(factory.type(), request.resourceRequest(), MemoryCache::removeFragmentIdentifierIfNeeded(request.url()), request.options(), request.forPreload(), request.getOriginRestriction()))
-        return nullptr;
+    if (!context().canRequest(factory.type(), request.resourceRequest(), MemoryCache::removeFragmentIdentifierIfNeeded(request.url()), request.options(), request.forPreload(), request.getOriginRestriction())) {
+        DCHECK(!substituteData.forceSynchronousLoad());
+        return resourceForBlockedRequest(request, factory);
+    }
 
     unsigned long identifier = createUniqueIdentifier();
     request.mutableResourceRequest().setPriority(computeLoadPriority(factory.type(), request, ResourcePriority::NotVisible));
     initializeResourceRequest(request.mutableResourceRequest(), factory.type(), request.defer());
     context().willStartLoadingResource(identifier, request.mutableResourceRequest(), factory.type());
     if (!request.url().isValid())
         return nullptr;
 
     if (!request.forPreload()) {
         V8DOMActivityLogger* activityLogger = nullptr;
@@ skipping 914 matching lines @@
     visitor->trace(m_context);
     visitor->trace(m_archive);
     visitor->trace(m_loaders);
     visitor->trace(m_nonBlockingLoaders);
     visitor->trace(m_documentResources);
     visitor->trace(m_preloads);
     visitor->trace(m_resourceTimingInfoMap);
 }
 
 } // namespace blink