WebUI NTP: return HTML with data available for promo/OGB

If data is available, serve it immediately and refresh data. Most of the
time the data should be the same. The call should not wait until the
refresh completes before serving the data.

Change-Id: I8ed46e38f8256fa356645cdfc0019329b809ae67
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2164992
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#763017}

chrome/browser/ui/webui/new_tab_page/untrusted_source.cc

@@ -93,9 +93,10 @@ void UntrustedSource::StartDataRequest(
   GURL url_param = GURL(url.query());
   if (path == "one-google-bar" && one_google_bar_service_) {
     one_google_bar_callbacks_.push_back(std::move(callback));
-    if (one_google_bar_callbacks_.size() == 1) {
-      one_google_bar_service_->Refresh();
+    if (one_google_bar_service_->one_google_bar_data().has_value()) {
+      OnOneGoogleBarDataUpdated();
     }
+    one_google_bar_service_->Refresh();
     return;
   }
   if (path == "one_google_bar.js") {
@@ -106,9 +107,10 @@ void UntrustedSource::StartDataRequest(
   }
   if (path == "promo" && promo_service_) {
     promo_callbacks_.push_back(std::move(callback));
-    if (promo_callbacks_.size() == 1) {
-      promo_service_->Refresh();
+    if (promo_service_->promo_data().has_value()) {
+      OnPromoDataUpdated();
     }
+    promo_service_->Refresh();
     return;
   }
   if (path == "promo.js") {