When the download folder does not exist, change the download folder to a user's "Downloads"

content/browser/renderer_host/resource_dispatcher_host.cc

 // Copyright (c) 2011 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.h"
 
 #include <set>
 #include <vector>
@@ skipping 724 matching lines @@
 
   BeginRequestInternal(request);
 }
 
 // This function is only used for saving feature.
 void ResourceDispatcherHost::BeginSaveFile(
     const GURL& url,
     const GURL& referrer,
     int child_id,
     int route_id,
+    const FilePath& default_download_dir,
     const content::ResourceContext& context) {
   if (is_shutdown_)
     return;
 
   scoped_refptr<ResourceHandler> handler(
       new SaveFileResourceHandler(child_id,
                                   route_id,
                                   url,
+                                  default_download_dir,
                                   save_file_manager_.get()));
   request_id_--;
 
   const net::URLRequestContext* request_context = context.request_context();
   bool known_proto =
       request_context->job_factory()->IsHandledURL(url);
   if (!known_proto) {
     // Since any URLs which have non-standard scheme have been filtered
     // by save manager(see GURL::SchemeIsStandard). This situation
     // should not happen.
@@ skipping 1242 matching lines @@
   return HTTP_AUTH_RESOURCE_BLOCKED_CROSS;
 }
 
 bool ResourceDispatcherHost::allow_cross_origin_auth_prompt() {
   return allow_cross_origin_auth_prompt_;
 }
 
 void ResourceDispatcherHost::set_allow_cross_origin_auth_prompt(bool value) {
   allow_cross_origin_auth_prompt_ = value;
 }