Adding DRP specfic UMA for FirstContentfulPaint

content/browser/loader/navigation_resource_handler.h

Index: content/browser/loader/navigation_resource_handler.h
diff --git a/content/browser/loader/navigation_resource_handler.h b/content/browser/loader/navigation_resource_handler.h
index b5ba53572ca7fea81276482ac4a9e0519fdac708..cf8fc026bc91bbe9bb8a22d6d25b3ca2f01d0835 100644
--- a/content/browser/loader/navigation_resource_handler.h
+++ b/content/browser/loader/navigation_resource_handler.h
@@ -5,26 +5,29 @@
 #ifndef CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_HANDLER_H_
 #define CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_HANDLER_H_
 
 #include "base/macros.h"
 #include "content/browser/loader/resource_handler.h"
 #include "content/browser/loader/stream_writer.h"
 
 namespace content {
 
 class NavigationURLLoaderImplCore;
+class ResourceDispatcherHostDelegate;
 
 // PlzNavigate: The leaf ResourceHandler used with NavigationURLLoaderImplCore.
 class NavigationResourceHandler : public ResourceHandler {
  public:
-  NavigationResourceHandler(net::URLRequest* request,
-                            NavigationURLLoaderImplCore* core);
+  NavigationResourceHandler(
+      net::URLRequest* request,
+      NavigationURLLoaderImplCore* core,
+      ResourceDispatcherHostDelegate* resource_dispatcher_host_delegate);
   ~NavigationResourceHandler() override;
 
   // Called by the loader the cancel the request.
   void Cancel();
 
   // Called to the loader to resume a paused redirect.
   void FollowRedirect();
 
   // Called to proceed with the response.
   void ProceedWithResponse();
@@ -46,17 +49,18 @@ class NavigationResourceHandler : public ResourceHandler {
                            bool* defer) override;
   void OnDataDownloaded(int bytes_downloaded) override;
 
  private:
   // Clears |core_| and its reference to the resource handler. After calling
   // this, the lifetime of the request is no longer tied to |core_|.
   void DetachFromCore();
 
   NavigationURLLoaderImplCore* core_;
   StreamWriter writer_;
+  ResourceDispatcherHostDelegate* resource_dispatcher_host_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationResourceHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_HANDLER_H_