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

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index 2b006a25439bff555e7e7d2313489f3fbbd28bef..59807b48edff267c6fe77f10f3341d38bae26884 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -1543,9 +1543,9 @@ test("browser_tests") {
       "../browser/policy/policy_network_browsertest.cc",
       "../browser/policy/policy_prefs_browsertest.cc",
       "../browser/policy/policy_startup_browsertest.cc",
+      "../browser/predictors/loading_test_util.cc",
+      "../browser/predictors/loading_test_util.h",
       "../browser/predictors/resource_prefetch_predictor_browsertest.cc",
-      "../browser/predictors/resource_prefetch_predictor_test_util.cc",
-      "../browser/predictors/resource_prefetch_predictor_test_util.h",
       "../browser/prefetch/prefetch_browsertest.cc",
       "../browser/prefs/pref_functional_browsertest.cc",
       "../browser/prefs/pref_service_browsertest.cc",
@@ -3184,11 +3184,12 @@ test("unit_tests") {
     "../browser/policy/profile_policy_connector_unittest.cc",
     "../browser/predictors/autocomplete_action_predictor_table_unittest.cc",
     "../browser/predictors/autocomplete_action_predictor_unittest.cc",
+    "../browser/predictors/loading_data_collector_unittest.cc",
     "../browser/predictors/loading_predictor_unittest.cc",
+    "../browser/predictors/loading_test_util.cc",
+    "../browser/predictors/loading_test_util.h",
     "../browser/predictors/resource_prefetch_common_unittest.cc",
     "../browser/predictors/resource_prefetch_predictor_tables_unittest.cc",
-    "../browser/predictors/resource_prefetch_predictor_test_util.cc",
-    "../browser/predictors/resource_prefetch_predictor_test_util.h",
     "../browser/predictors/resource_prefetch_predictor_unittest.cc",
     "../browser/predictors/resource_prefetcher_unittest.cc",
     "../browser/prefs/chrome_command_line_pref_store_proxy_unittest.cc",