Use ByteStream in downloads system to decouple source and sink.

content/browser/renderer_host/resource_dispatcher_host_impl.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/resource_dispatcher_host_impl.h"
 
 #include <set>
 #include <vector>
@@ skipping 555 matching lines @@
     net::URLRequest* request,
     ResourceContext* context,
     int child_id,
     int route_id,
     int request_id,
     bool is_content_initiated,
     const DownloadSaveInfo& save_info,
     const DownloadResourceHandler::OnStartedCallback& started_cb) {
   scoped_refptr<ResourceHandler> handler(
       new DownloadResourceHandler(child_id, route_id, request_id,
-                                  request->url(), download_file_manager_.get(),
+                                  request->url(), download_file_manager_,
                                   request, started_cb, save_info));
   if (delegate_) {
     ScopedVector<ResourceThrottle> throttles;
     delegate_->DownloadStarting(request, context, child_id, route_id,
                                 request_id, is_content_initiated, &throttles);
     if (!throttles.empty()) {
       handler = new ThrottlingResourceHandler(this, handler, child_id,
                                               request_id, throttles.Pass());
     }
   }
@@ skipping 1774 matching lines @@
   return allow_cross_origin_auth_prompt_;
 }
 
 bool ResourceDispatcherHostImpl::IsTransferredNavigation(
     const GlobalRequestID& transferred_request_id) const {
   return transferred_navigations_.find(transferred_request_id) !=
       transferred_navigations_.end();
 }
 
 }  // namespace content