Adding DRP specfic UMA for FirstContentfulPaint

content/public/common/resource_response_info.h

Index: content/public/common/resource_response_info.h
diff --git a/content/public/common/resource_response_info.h b/content/public/common/resource_response_info.h
index 340407ecc5951b2b42eab70267972312e5223eec..ad2593772cc75071e5a5993badc10b48f43caa2d 100644
--- a/content/public/common/resource_response_info.h
+++ b/content/public/common/resource_response_info.h
@@ -128,17 +128,20 @@ struct ResourceResponseInfo {
   // The time immediately before starting ServiceWorker. If the response is not
   // provided by the ServiceWorker, kept empty.
   // TODO(ksakamoto): Move this to net::LoadTimingInfo.
   base::TimeTicks service_worker_start_time;
 
   // The time immediately before dispatching fetch event in ServiceWorker.
   // If the response is not provided by the ServiceWorker, kept empty.
   // TODO(ksakamoto): Move this to net::LoadTimingInfo.
   base::TimeTicks service_worker_ready_time;
 
-  // Whether or not the request was for a LoFi version of the resource.
+  // True if the navigation used lofi.
   bool is_using_lofi;
+
+  // True if the navigation was proxied through data reduction proxy.
+  bool used_data_reduction_proxy;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_RESOURCE_RESPONSE_INFO_H_