Use the suggested name from an anchor's 'download' attribute.

content/renderer/render_view.h

 // 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.
 
 #ifndef CONTENT_RENDERER_RENDER_VIEW_H_
 #define CONTENT_RENDERER_RENDER_VIEW_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 434 matching lines @@
       WebKit::WebMediaPlayerClient* client);
   virtual WebKit::WebApplicationCacheHost* createApplicationCacheHost(
       WebKit::WebFrame* frame,
       WebKit::WebApplicationCacheHostClient* client);
   virtual WebKit::WebCookieJar* cookieJar(WebKit::WebFrame* frame);
   virtual void frameDetached(WebKit::WebFrame* frame);
   virtual void willClose(WebKit::WebFrame* frame);
   virtual void loadURLExternally(WebKit::WebFrame* frame,
                                  const WebKit::WebURLRequest& request,
                                  WebKit::WebNavigationPolicy policy);
+  virtual void loadURLExternally(WebKit::WebFrame* frame,
+                                 const WebKit::WebURLRequest& request,
+                                 WebKit::WebNavigationPolicy policy,
+                                 const WebKit::WebString& suggested_name);
   virtual WebKit::WebNavigationPolicy decidePolicyForNavigation(
       WebKit::WebFrame* frame,
       const WebKit::WebURLRequest& request,
       WebKit::WebNavigationType type,
       const WebKit::WebNode&,
       WebKit::WebNavigationPolicy default_policy,
       bool is_redirect);
   virtual bool canHandleRequest(WebKit::WebFrame* frame,
                                 const WebKit::WebURLRequest& request);
   virtual WebKit::WebURLError cannotHandleRequestError(
@@ skipping 708 matching lines @@
   // bunch of stuff, you should probably create a helper class and put your
   // data and methods on that to avoid bloating RenderView more.  You can use
   // the Observer interface to filter IPC messages and receive frame change
   // notifications.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(RenderView);
 };
 
 #endif  // CONTENT_RENDERER_RENDER_VIEW_H_