Change URLRequest to use a ref-counted buffer for actual IO....

chrome/browser/renderer_host/save_file_resource_handler.h

Index: chrome/browser/renderer_host/save_file_resource_handler.h
===================================================================
--- chrome/browser/renderer_host/save_file_resource_handler.h	(revision 8565)
+++ chrome/browser/renderer_host/save_file_resource_handler.h	(working copy)
@@ -28,7 +28,8 @@
 
   // Creates a new buffer, which will be handed to the download thread for file
   // writing and deletion.
-  bool OnWillRead(int request_id, char** buf, int* buf_size, int min_size);
+  bool OnWillRead(int request_id, net::IOBuffer** buf, int* buf_size,
+                  int min_size);
 
   // Passes the buffer to the download file writer.
   bool OnReadCompleted(int request_id, int* bytes_read);
@@ -50,7 +51,7 @@
   int save_id_;
   int render_process_id_;
   int render_view_id_;
-  char* read_buffer_;
+  scoped_refptr<net::IOBuffer> read_buffer_;
   std::string content_disposition_;
   std::wstring url_;
   std::wstring final_url_;