[ServiceWorker] Make fetch() method better conformance with the spec.

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 1281 matching lines @@
     context().dispatchDidFail(m_documentLoader, resource->identifier(), error);
 }
 
 void ResourceFetcher::willSendRequest(unsigned long identifier, ResourceRequest& request, const ResourceResponse& redirectResponse, const FetchInitiatorInfo& initiatorInfo)
 {
     context().dispatchWillSendRequest(m_documentLoader, identifier, request, redirectResponse, initiatorInfo);
 }
 
 void ResourceFetcher::didReceiveResponse(const Resource* resource, const ResourceResponse& response)
 {
-    // FIXME: When response.wasFetchedViaServiceWorker() is true, we need to check the URL of the responce for CSP and CORS.
+    // If the response is fetched via ServiceWorker, the original URL of the response could be different from the URL of the request.
+    if (response.wasFetchedViaServiceWorker()) {
+        if (!canRequest(resource->type(), resource->lastResourceRequest().requestContext(), response.url(), resource->options(), false, FetchRequest::UseDefaultOriginRestrictionForType)) {
+            resource->loader()->cancel();
+            context().dispatchDidFail(m_documentLoader, resource->identifier(), ResourceError(errorDomainBlinkInternal, 0, response.url().string(), "Original url check of ServiceWorker fetched resource failed."));

[jochen (gone - plz use gerrit), 2014/07/24 14:37:26]

the error message would leave me a bit confused about what actually went wrong.
Can we do better?

[horo, 2014/07/24 15:50:22]

Done.

+            return;
+        }
+    }
     context().dispatchDidReceiveResponse(m_documentLoader, resource->identifier(), response, resource->loader());
 }
 
 void ResourceFetcher::didReceiveData(const Resource* resource, const char* data, int dataLength, int encodedDataLength)
 {
     context().dispatchDidReceiveData(m_documentLoader, resource->identifier(), data, dataLength, encodedDataLength);
 }
 
 void ResourceFetcher::didDownloadData(const Resource* resource, int dataLength, int encodedDataLength)
 {
@@ skipping 196 matching lines @@
     }
 }
 
 void ResourceFetcher::trace(Visitor* visitor)
 {
     visitor->trace(m_document);
     ResourceLoaderHost::trace(visitor);
 }
 
 }