Use ByteStream in downloads system to decouple source and sink.

content/browser/renderer_host/x509_user_cert_resource_handler.h

Index: content/browser/renderer_host/x509_user_cert_resource_handler.h
diff --git a/content/browser/renderer_host/x509_user_cert_resource_handler.h b/content/browser/renderer_host/x509_user_cert_resource_handler.h
index 9dcfa50b91710a9c01f6c27eb3ef1856485012a8..eb8bd7f3d92c5da105d7ff1cd6de59a839671539 100644
--- a/content/browser/renderer_host/x509_user_cert_resource_handler.h
+++ b/content/browser/renderer_host/x509_user_cert_resource_handler.h
@@ -7,10 +7,12 @@
 #pragma once
 
 #include <string>
+#include <utility>
+#include <vector>
 
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/ref_counted.h"
-#include "content/browser/download/download_buffer.h"
 #include "content/browser/renderer_host/resource_handler.h"
 #include "googleurl/src/gurl.h"
 
@@ -69,6 +71,9 @@ class X509UserCertResourceHandler : public ResourceHandler {
   virtual void OnRequestClosed() OVERRIDE;
 
  private:
+  typedef std::vector<std::pair<scoped_refptr<net::IOBuffer>,
+                                size_t> > ContentVector;
+
   virtual ~X509UserCertResourceHandler();
 
   void AssembleResource();
@@ -76,7 +81,7 @@ class X509UserCertResourceHandler : public ResourceHandler {
   GURL url_;
   net::URLRequest* request_;
   size_t content_length_;
-  content::ContentVector buffer_;
+  ContentVector buffer_;
   scoped_refptr<net::IOBuffer> read_buffer_;
   scoped_refptr<net::IOBuffer> resource_buffer_;  // Downloaded certificate.
   // The id of the |RenderProcessHost| which started the download.