Avoid reusing XMLHttpRequest resources during document load.

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 842 matching lines @@
     // with this one, or vice versa, re-fetch the resource.
     //
     // This helps with the case where the server sends back
     // "Access-Control-Allow-Origin: *" all the time, but some of the
     // client's requests are made without CORS and some with.
     if (existingResource->resourceRequest().allowCookies() != request.allowCookies()) {
         LOG(ResourceLoading, "ResourceFetcher::determineRevalidationPolicy reloading due to difference in credentials settings.");
         return Reload;
     }
 
+    // For compatibility, reload existing resource with a Raw type (read: XHR.)
+    if (type == Resource::Raw)

[Nate Chapin, 2013/11/05 19:39:24]

We probably want a narrower fix than this. RawResource::canReuse() permits reuse
in a much narrower set of cases than other resources, but it's possible that
it's still too permissive. Regardless, the fix should probably go there.

Based on the test case you provided, perhaps canReuse() should check whether
either the existing or the new request have a url with a query?

+        return Reload;
+
     // During the initial load, avoid loading the same resource multiple times for a single document, even if the cache policies would tell us to.
     if (document() && !document()->loadEventFinished() && m_validatedURLs.contains(existingResource->url()))
         return Use;
 
     // CachePolicyReload always reloads
     if (context().cachePolicy(type) == CachePolicyReload) {
         LOG(ResourceLoading, "ResourceFetcher::determineRevalidationPolicy reloading due to CachePolicyReload.");
         return Reload;
     }
 
@@ skipping 447 matching lines @@
 }
 #endif
 
 const ResourceLoaderOptions& ResourceFetcher::defaultResourceOptions()
 {
     DEFINE_STATIC_LOCAL(ResourceLoaderOptions, options, (SendCallbacks, SniffContent, BufferData, AllowStoredCredentials, ClientRequestedCredentials, AskClientForCrossOriginCredentials, DoSecurityCheck, CheckContentSecurityPolicy, UseDefaultOriginRestrictionsForType, DocumentContext));
     return options;
 }
 
 }