Periodically remove old pending navigation entries.

chrome/browser/data_use_measurement/chrome_data_use_ascriber.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_H_
 #define CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_H_
 
 #include <list>
 #include <memory>
 #include <unordered_map>
@@ skipping 81 matching lines @@
       bool is_same_page_navigation,
       void* navigation_handle);
 
   // Called when a main frame navigation is redirected.
   void DidRedirectMainFrameNavigation(GURL gurl,
                                       int render_process_id,
                                       int render_frame_id,
                                       void* navigation_handle);
 
  private:
+  friend class ChromeDataUseAscriberTest;
+
   // Use as a key in the render frame map. Corresponds to a unique
   // RenderFrameHost.
   typedef std::pair<int, int> RenderFrameHostID;
 
   // Entry in the |data_use_recorders_| list which owns all instances of
   // DataUseRecorder.
   typedef std::list<std::unique_ptr<data_use_measurement::DataUseRecorder>>::
       iterator DataUseRecorderEntry;
 
   struct GlobalRequestIDHash {
@@ skipping 12 matching lines @@
     DataUseRecorderEntry recorder_entry() { return entry_; }
 
     static const void* kUserDataKey;
 
    private:
     DataUseRecorderEntry entry_;
   };
 
   void DeletePendingNavigationEntry(content::GlobalRequestID global_request_id);
 
+  // The ReadyToCommitNavigation() callback is used to remove entries from
+  // |pending_navigation_data_use_map_|. However, there are a number of race
+  // conditions which make this callback unreliable until PlzNavigate is used.
+  // Until then, this method periodically deletes old navigation entries
+  // that have finished data use.
+  void DeleteOldPendingNavigationEntries(base::Time now);
+
   // Owner for all instances of DataUseRecorder. An instance is kept in this
   // list if any entity (render frame hosts, URLRequests, pending navigations)
   // that ascribe data use to the instance exists, and deleted when all
   // ascribing entities go away.
   std::list<std::unique_ptr<DataUseRecorder>> data_use_recorders_;
 
   // Map from RenderFrameHost to the DataUseRecorderEntry in
   // |data_use_recorders_| that the frame ascribe data use to.
   base::hash_map<RenderFrameHostID, DataUseRecorderEntry>
       render_frame_data_use_map_;
 
   // Map from pending navigations to the DataUseRecorderEntry in
   // |data_use_recorders_| that the navigation ascribes data use to.
   std::unordered_map<content::GlobalRequestID,
                      DataUseRecorderEntry,
                      GlobalRequestIDHash>
       pending_navigation_data_use_map_;
 
+  base::Time last_pending_navigations_discard_time_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeDataUseAscriber);
 };
 
 }  // namespace data_use_measurement
 
 #endif  // CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_H_