Create LoadingDataCollector class and have observers rely on it instead of ResourcePrefetchPredictor

chrome/browser/page_load_metrics/page_load_metrics_initialize.cc

Index: chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
index c0c3791caf18639b73a34e44fcd106d99cc26698..542c4d2e26d72bfdff61b6b2ee3f203a54d6d621 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
+++ b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
@@ -121,11 +121,11 @@ void PageLoadMetricsEmbedder::RegisterObservers(
         base::MakeUnique<AndroidPageLoadMetricsObserver>(web_contents_));
 #endif  // OS_ANDROID
     std::unique_ptr<page_load_metrics::PageLoadMetricsObserver>
-        resource_prefetch_predictor_observer =
+        loading_predictor_observer =
             ResourcePrefetchPredictorPageLoadMetricsObserver::CreateIfNeeded(
                 web_contents_);
-    if (resource_prefetch_predictor_observer)
-      tracker->AddObserver(std::move(resource_prefetch_predictor_observer));
+    if (loading_predictor_observer)
+      tracker->AddObserver(std::move(loading_predictor_observer));
   } else {
     std::unique_ptr<page_load_metrics::PageLoadMetricsObserver>
         prerender_observer =