Add one more histogram to log how many Request are still pending when

net/http/http_stream_factory_impl_job_controller.h

Index: net/http/http_stream_factory_impl_job_controller.h
diff --git a/net/http/http_stream_factory_impl_job_controller.h b/net/http/http_stream_factory_impl_job_controller.h
index 9a43bfb61499357648b6eadd32c3769cd66d5342..a27b482a7cbcc0b504b37071a1c7d2387be46651 100644
--- a/net/http/http_stream_factory_impl_job_controller.h
+++ b/net/http/http_stream_factory_impl_job_controller.h
@@ -172,6 +172,9 @@ class HttpStreamFactoryImpl::JobController
 
   bool is_preconnect() const { return is_preconnect_; }
 
+  // Returns true if |this| has a pending request that is not completed.
+  bool HasPendingRequest() const { return request_ != nullptr; }
+
   // Returns true if |this| has a pending main job that is not completed.
   bool HasPendingMainJob() const;