net: Allow URLFetcher users to inject custom URLFetcherResponseWriter

net/url_request/url_fetcher_impl.cc

Index: net/url_request/url_fetcher_impl.cc
diff --git a/net/url_request/url_fetcher_impl.cc b/net/url_request/url_fetcher_impl.cc
index 9d73ba08b0dea9d9d1b6eb3e7289dd386633ba6c..c3fc6461cf85b2478be54002ef829b307e2d1742 100644
--- a/net/url_request/url_fetcher_impl.cc
+++ b/net/url_request/url_fetcher_impl.cc
@@ -8,6 +8,7 @@
 #include "base/message_loop/message_loop_proxy.h"
 #include "net/url_request/url_fetcher_core.h"
 #include "net/url_request/url_fetcher_factory.h"
+#include "net/url_request/url_fetcher_response_writer.h"
 
 namespace net {
 
@@ -129,6 +130,11 @@ void URLFetcherImpl::SaveResponseToTemporaryFile(
   core_->SaveResponseToTemporaryFile(file_task_runner);
 }
 
+void URLFetcherImpl::SaveResponseWithWriter(
+    scoped_ptr<URLFetcherResponseWriter> response_writer) {
+  core_->SaveResponseWithWriter(response_writer.Pass());
+}
+
 HttpResponseHeaders* URLFetcherImpl::GetResponseHeaders() const {
   return core_->GetResponseHeaders();
 }