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

chrome/browser/predictors/loading_predictor.h

Index: chrome/browser/predictors/loading_predictor.h
diff --git a/chrome/browser/predictors/loading_predictor.h b/chrome/browser/predictors/loading_predictor.h
index eb1d29ad5065e6a74b6e5ac650584b7ce925c326..e9db23a3568aced9c4a4e99e2ac34f471eb7c4a9 100644
--- a/chrome/browser/predictors/loading_predictor.h
+++ b/chrome/browser/predictors/loading_predictor.h
@@ -12,6 +12,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.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 "components/keyed_service/core/keyed_service.h"
@@ -53,6 +54,7 @@ class LoadingPredictor : public KeyedService,
 
   // Don't use, internal only.
   ResourcePrefetchPredictor* resource_prefetch_predictor() const;

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

nit:
These methods should be non-const because we return non-const handles to
internal data of object.
More context:
https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source=f...

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

Done.

+  LoadingDataCollector* loading_data_collector() const;
 
   // KeyedService:
   void Shutdown() override;
@@ -82,6 +84,7 @@ class LoadingPredictor : public KeyedService,
   Profile* profile_;
   std::unique_ptr<ResourcePrefetchPredictor> resource_prefetch_predictor_;
   std::unique_ptr<LoadingStatsCollector> stats_collector_;
+  std::unique_ptr<LoadingDataCollector> loading_data_collector_;
   std::map<GURL, base::TimeTicks> active_hints_;
   // Initial URL.
   std::map<NavigationID, GURL> active_navigations_;