Send fatal proxy errors to the network delegate.

net/url_request/url_request.cc

Index: net/url_request/url_request.cc
diff --git a/net/url_request/url_request.cc b/net/url_request/url_request.cc
index 9e35fc0d58ff3b8cf9ca2f4ab494e3bc3138f367..44994f063215af61ba05ff8724b32147dafc23db 100644
--- a/net/url_request/url_request.cc
+++ b/net/url_request/url_request.cc
@@ -486,8 +486,11 @@ void URLRequest::ResponseStarted() {
       URLRequestJobManager::GetInstance()->MaybeInterceptResponse(this);
   if (job) {
     RestartWithJob(job);
-  } else if (delegate_) {
-    delegate_->OnResponseStarted(this);
+  } else {
+    if (context_ && context_->network_delegate())
+      context_->network_delegate()->OnResponseStarted(this);
+    if (delegate_)
+      delegate_->OnResponseStarted(this);
   }
 }