Make ResourceFetcher return Resources with LoadError instead of nullptrs.

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

Index: third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
diff --git a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
index c0f613969580a630fdd489a41334a493fedae28e..b51bcedff964eb9c4d8fe8af4166a01490e8cd86 100644
--- a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
+++ b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
@@ -375,6 +375,13 @@ Resource* ResourceFetcher::resourceForStaticData(const FetchRequest& request, co
     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.
@@ -419,8 +426,10 @@ Resource* ResourceFetcher::requestResource(FetchRequest& request, const Resource
     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));