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..14450b64607f671193a2c54df55e3c1d0dbd323e 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
+++ b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
@@ -4,6 +4,9 @@
 
 #include "chrome/browser/page_load_metrics/page_load_metrics_initialize.h"
 
+#include <memory>
+#include <utility>
+
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/timer/timer.h"
@@ -121,11 +124,11 @@ 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(

[alexilin, 2017/06/07 12:37:31]

nit:
We could rename ResourcePrefetchPredictorPageLoadMetricsObserver class to
LoadingPredictorPageLoadMetricsObserver as well.

[trevordixon, 2017/06/07 13:17:55]

OK, done.

                 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 =