predictors: Remove resources marked as unused.

chrome/browser/predictors/resource_prefetch_predictor.h

Index: chrome/browser/predictors/resource_prefetch_predictor.h
diff --git a/chrome/browser/predictors/resource_prefetch_predictor.h b/chrome/browser/predictors/resource_prefetch_predictor.h
index 242de6bca0d790734c4f5dc94ab5951d09c202bf..750ac83bf01caf114b54e73ea326ccb7b759b08f 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor.h
+++ b/chrome/browser/predictors/resource_prefetch_predictor.h
@@ -62,6 +62,8 @@ constexpr char kResourcePrefetchPredictorPrefetchMissesSize[] =
     "ResourcePrefetchPredictor.PrefetchMissesSizeKB";
 constexpr char kResourcePrefetchPredictorRedirectStatusHistogram[] =
     "ResourcePrefetchPredictor.RedirectStatus";
+
+const uint32_t kUnusedRemovedExperiment = 0xf7f77166;
 }  // namespace internal
 
 class TestObserver;
@@ -276,6 +278,8 @@ class ResourcePrefetchPredictor
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, ManifestHostInDB);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
                            ManifestHostNotInDBAndDBFull);
+  FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
+                           ManifestUnusedRemoved);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, OnMainFrameRequest);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest, OnMainFrameRedirect);
   FRIEND_TEST_ALL_PREFIXES(ResourcePrefetchPredictorTest,
@@ -435,6 +439,13 @@ class ResourcePrefetchPredictor
   void OnHistoryServiceLoaded(
       history::HistoryService* history_service) override;
 
+  // Updates list of resources in the |data_map| for the |key| according to the
+  // |manifest|.
+  void UpdatePrefetchDataByManifest(const std::string& key,
+                                    PrefetchKeyType key_type,
+                                    PrefetchDataMap* data_map,
+                                    const precache::PrecacheManifest& manifest);
+
   // Used to connect to HistoryService or register for service loaded
   // notificatioan.
   void ConnectToHistoryService();