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

chrome/browser/page_load_metrics/observers/resource_prefetch_predictor_page_load_metrics_observer_unittest.cc

Index: chrome/browser/page_load_metrics/observers/resource_prefetch_predictor_page_load_metrics_observer_unittest.cc
diff --git a/chrome/browser/page_load_metrics/observers/resource_prefetch_predictor_page_load_metrics_observer_unittest.cc b/chrome/browser/page_load_metrics/observers/resource_prefetch_predictor_page_load_metrics_observer_unittest.cc
index 64cbc254766ba6839ad419f4755b2126ba350e0b..6238d2f12779cb2bf04ceabeccd3b9068e3f4ba9 100644
--- a/chrome/browser/page_load_metrics/observers/resource_prefetch_predictor_page_load_metrics_observer_unittest.cc
+++ b/chrome/browser/page_load_metrics/observers/resource_prefetch_predictor_page_load_metrics_observer_unittest.cc
@@ -8,12 +8,14 @@
 
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h"
+#include "chrome/browser/predictors/loading_data_collector.h"
 #include "chrome/browser/predictors/resource_prefetch_common.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
+using predictors::LoadingDataCollector;
 using predictors::ResourcePrefetchPredictor;
 
 class MockResourcePrefetchPredictor : public ResourcePrefetchPredictor {
@@ -39,6 +41,7 @@ class ResourcePrefetchPredictorPageLoadMetricsObserverTest
         base::MakeUnique<testing::StrictMock<MockResourcePrefetchPredictor>>(
             config, profile());
     page_load_metrics::InitPageLoadTimingForTest(&timing_);
+    collector_ = base::MakeUnique<LoadingDataCollector>(predictor_.get());
     timing_.navigation_start = base::Time::FromDoubleT(1);
     timing_.paint_timing->first_paint = base::TimeDelta::FromSeconds(2);
     timing_.paint_timing->first_contentful_paint =
@@ -51,12 +54,13 @@ class ResourcePrefetchPredictorPageLoadMetricsObserverTest
   void RegisterObservers(page_load_metrics::PageLoadTracker* tracker) override {
     tracker->AddObserver(
         base::MakeUnique<ResourcePrefetchPredictorPageLoadMetricsObserver>(
-            predictor_.get(), web_contents()));
+            predictor_.get(), collector_.get(), web_contents()));
   }
 
   std::unique_ptr<testing::StrictMock<MockResourcePrefetchPredictor>>
       predictor_;
   page_load_metrics::mojom::PageLoadTiming timing_;
+  std::unique_ptr<LoadingDataCollector> collector_;
 };
 
 TEST_F(ResourcePrefetchPredictorPageLoadMetricsObserverTest,