Add 'XHR' to the Resource::Type enum, and use it for XHR requests.

Source/core/fetch/RawResource.h

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 
     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
     version 2 of the License, or (at your option) any later version.
@@ skipping 42 matching lines @@
     virtual void updateRequest(const ResourceRequest&) OVERRIDE;
     virtual void responseReceived(const ResourceResponse&) OVERRIDE;
     virtual void didSendData(unsigned long long bytesSent, unsigned long long totalBytesToBeSent) OVERRIDE;
     virtual void didDownloadData(int) OVERRIDE;
 };
 
 #ifdef SECURITY_ASSERT_ENABLED
 inline bool isRawResource(const Resource& resource)
 {
     Resource::Type type = resource.type();
-    return type == Resource::MainResource || type == Resource::Raw || type == Resource::TextTrack || type == Resource::Media || type == Resource::ImportResource;
+    return type == Resource::MainResource || type == Resource::Raw || type == Resource::TextTrack || type == Resource::Media || type == Resource::ImportResource || type == Resource::XMLHttpRequest;
 }
 #endif
 inline RawResource* toRawResource(const ResourcePtr<Resource>& resource)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!resource || isRawResource(*resource.get()));
     return static_cast<RawResource*>(resource.get());
 }
 
 class RawResourceClient : public ResourceClient {
 public:
     virtual ~RawResourceClient() { }
     static ResourceClientType expectedType() { return RawResourceType; }
     virtual ResourceClientType resourceClientType() const OVERRIDE FINAL { return expectedType(); }
 
     virtual void dataSent(Resource*, unsigned long long /* bytesSent */, unsigned long long /* totalBytesToBeSent */) { }
     virtual void responseReceived(Resource*, const ResourceResponse&) { }
     virtual void dataReceived(Resource*, const char* /* data */, int /* length */) { }
     virtual void redirectReceived(Resource*, ResourceRequest&, const ResourceResponse&) { }
     virtual void updateRequest(Resource*, const ResourceRequest&) { }
     virtual void dataDownloaded(Resource*, int) { }
 };
 
 }
 
 #endif // RawResource_h