Adding DRP specfic UMA for FirstContentfulPaint

content/test/test_render_frame_host.cc

Index: content/test/test_render_frame_host.cc
diff --git a/content/test/test_render_frame_host.cc b/content/test/test_render_frame_host.cc
index 508f7200065690bdc5ef1c453335f59b823cfdc6..a9690849aebe7820ecfa6a4552ef2e3217b179f0 100644
--- a/content/test/test_render_frame_host.cc
+++ b/content/test/test_render_frame_host.cc
@@ -413,21 +413,21 @@ void TestRenderFrameHost::PrepareForCommitWithServerRedirect(
   CHECK(url_loader);
 
   // If a non-empty |redirect_url| was provided, simulate a server redirect.
   if (!redirect_url.is_empty())
     url_loader->SimulateServerRedirect(redirect_url);
 
   // Simulate the network stack commit.
   scoped_refptr<ResourceResponse> response(new ResourceResponse);
   // TODO(carlosk): ideally with PlzNavigate it should be possible someday to
   // fully commit the navigation at this call to CallOnResponseStarted.
-  url_loader->CallOnResponseStarted(response, MakeEmptyStream());
+  url_loader->CallOnResponseStarted(response, MakeEmptyStream(), nullptr);
 }
 
 int32_t TestRenderFrameHost::ComputeNextPageID() {
   const NavigationEntryImpl* entry = static_cast<NavigationEntryImpl*>(
       frame_tree_node()->navigator()->GetController()->GetPendingEntry());
   DCHECK(!(entry && entry->site_instance()) ||
          entry->site_instance() == GetSiteInstance());
   // Entry can be null when committing an error page (the pending entry was
   // cleared during DidFailProvisionalLoad).
   int page_id = entry ? entry->GetPageID() : -1;