Give the filter setup more context so it can figure out whether it's download...

chrome/browser/renderer_host/resource_dispatcher_host.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
 
 #include <vector>
 
@@ skipping 506 matching lines @@
   }
 
   bool known_proto = URLRequest::IsHandledURL(url);
   if (!known_proto) {
     CHECK(false);
   }
 
   request->set_method("GET");
   request->set_referrer(referrer.spec());
   request->set_context(request_context);
+  request->set_load_flags(request->load_flags() |
+      net::LOAD_IS_DOWNLOAD);
 
   ExtraRequestInfo* extra_info =
       new ExtraRequestInfo(handler,
                            ChildProcessInfo::RENDER_PROCESS,
                            process_id,
                            route_id,
                            request_id_,
                            "null",  // frame_origin
                            "null",  // main_frame_origin
                            ResourceType::SUB_RESOURCE,
@@ skipping 1014 matching lines @@
     case ViewHostMsg_UploadProgress_ACK::ID:
     case ViewHostMsg_SyncLoad::ID:
       return true;
 
     default:
       break;
   }
 
   return false;
 }