Allow URLRequests from one context to have different NetworkDelegates.

net/url_request/url_request_http_job.cc

Index: net/url_request/url_request_http_job.cc
diff --git a/net/url_request/url_request_http_job.cc b/net/url_request/url_request_http_job.cc
index 8c450b5c806e3c7bffaa18353c4626e99bb4a6ee..b087e4dcfc080579f5527b066b118617c0d63c99 100644
--- a/net/url_request/url_request_http_job.cc
+++ b/net/url_request/url_request_http_job.cc
@@ -448,8 +448,9 @@ void URLRequestHttpJob::StartTransactionInternal() {
           base::Bind(&URLRequestHttpJob::NotifyBeforeSendProxyHeadersCallback,
                      base::Unretained(this)));
 
-      if (!throttling_entry_.get() ||
-          !throttling_entry_->ShouldRejectRequest(*request_)) {
+      if (!throttling_entry_ ||
+          !throttling_entry_->ShouldRejectRequest(
+              *request_, network_delegate())) {
         rv = transaction_->Start(
             &request_info_, start_callback_, request_->net_log());
         start_time_ = base::TimeTicks::Now();