Removed request_tracker_data_memoizing_store.h as unused.

Bug: 585700
Change-Id: Ie237264dd235db8c499608fd0b53fb79d50c8859
Reviewed-on: https://chromium-review.googlesource.com/691100Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505382}

ios/web/BUILD.gn

@@ -104,7 +104,6 @@ source_set("web") {
     "net/crw_ssl_status_updater.mm",
     "net/request_group_util.h",
     "net/request_group_util.mm",
-    "net/request_tracker_data_memoizing_store.h",
     "net/request_tracker_factory_impl.h",
     "net/request_tracker_factory_impl.mm",
     "net/request_tracker_impl.h",

ios/web/net/request_tracker_data_memoizing_store.h

-// Copyright 2015 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 IOS_WEB_NET_REQUEST_TRACKER_DATA_MEMOIZING_STORE_H_
-#define IOS_WEB_NET_REQUEST_TRACKER_DATA_MEMOIZING_STORE_H_
-
-#include <map>
-
-#include "base/bind.h"
-#include "base/synchronization/lock.h"
-#include "ios/web/public/web_thread.h"
-
-namespace web {
-
-// RequestTrackerDataMemoizingStore is a thread-safe container that retains
-// reference counted objects that are associated with one or more request
-// trackers. Objects are identified by an int and only a single reference to a
-// given object is retained.
-template <typename T>
-class RequestTrackerDataMemoizingStore {
- public:
-  RequestTrackerDataMemoizingStore() : next_item_id_(1) {}
-
-  ~RequestTrackerDataMemoizingStore() {
-    DCHECK_EQ(0U, id_to_item_.size()) << "Failed to outlive request tracker";
-  }
-
-  // Store adds |item| to this collection, associates it with the given request
-  // tracker id and returns an opaque identifier for it. If |item| is already
-  // known, the same identifier will be returned.
-  int Store(T* item, int request_tracker_id) {
-    DCHECK(item);
-    base::AutoLock auto_lock(lock_);
-
-    int item_id = 0;
-
-    // Is this item alread known?
-    typename ReverseItemMap::iterator item_iter = item_to_id_.find(item);
-    if (item_iter == item_to_id_.end()) {
-      item_id = next_item_id_++;
-      // Use 0 as an invalid item_id value.  In the unlikely event that
-      // next_item_id_ wraps around, reset it to 1.
-      if (next_item_id_ == 0)
-        next_item_id_ = 1;
-      id_to_item_[item_id] = item;
-      item_to_id_[item] = item_id;
-    } else {
-      item_id = item_iter->second;
-    }
-
-    // Update the bidirection request_tracker_id and item_id mappings.
-    UpdateMap(&request_tracker_id_to_item_id_, request_tracker_id, item_id);
-    UpdateMap(&item_id_to_request_tracker_id_, item_id, request_tracker_id);
-
-    DCHECK(item_id);
-    return item_id;
-  }
-
-  // Retrieves a previously Stored() item, identified by |item_id|.
-  // If |item_id| is recognized, |item| will be updated and Retrieve() will
-  // return true.
-  bool Retrieve(int item_id, scoped_refptr<T>* item) {
-    base::AutoLock auto_lock(lock_);
-
-    typename ItemMap::iterator iter = id_to_item_.find(item_id);
-    if (iter == id_to_item_.end())
-      return false;
-    if (item)
-      *item = iter->second;
-    return true;
-  }
-
-  // Removes any items associtated only with |request_tracker_id|.
-  void RemoveForRequestTracker(int request_tracker_id) {
-    RemoveRequestTrackerItems(request_tracker_id);
-  }
-
- private:
-  typedef std::multimap<int, int> IDMap;
-  typedef std::map<int, scoped_refptr<T>> ItemMap;
-  typedef std::map<T*, int, typename T::LessThan> ReverseItemMap;
-
-  template <typename M>
-  struct MatchSecond {
-    explicit MatchSecond(const M& t) : value(t) {}
-
-    template <typename Pair>
-    bool operator()(const Pair& p) const {
-      return (value == p.second);
-    }
-
-    M value;
-  };
-
-  // Updates |map| to contain a key_id->value_id pair, ensuring that a duplicate
-  // pair is not added if it was already present.
-  static void UpdateMap(IDMap* map, int key_id, int value_id) {
-    auto matching_key_range = map->equal_range(key_id);
-    if (std::find_if(matching_key_range.first, matching_key_range.second,
-                     MatchSecond<int>(value_id)) == matching_key_range.second) {
-      map->insert(std::make_pair(key_id, value_id));
-    }
-  }
-
-  // Remove the item specified by |item_id| from id_to_item_ and item_to_id_.
-  // NOTE: the caller (RemoveRequestTrackerItems) must hold lock_.
-  void RemoveInternal(int item_id) {
-    typename ItemMap::iterator item_iter = id_to_item_.find(item_id);
-    DCHECK(item_iter != id_to_item_.end());
-
-    typename ReverseItemMap::iterator id_iter =
-        item_to_id_.find(item_iter->second.get());
-    DCHECK(id_iter != item_to_id_.end());
-    item_to_id_.erase(id_iter);
-
-    id_to_item_.erase(item_iter);
-  }
-
-  // Removes all the items associated with the specified request tracker from
-  // the store.
-  void RemoveRequestTrackerItems(int request_tracker_id) {
-    base::AutoLock auto_lock(lock_);
-
-    // Iterate through all the item ids for that request tracker.
-    auto request_tracker_ids =
-        request_tracker_id_to_item_id_.equal_range(request_tracker_id);
-    for (IDMap::iterator ids_iter = request_tracker_ids.first;
-         ids_iter != request_tracker_ids.second; ++ids_iter) {
-      int item_id = ids_iter->second;
-      // Find all the request trackers referring to this item id in
-      // item_id_to_request_tracker_id_, then locate the request tracker being
-      // removed within that range.
-      auto item_ids = item_id_to_request_tracker_id_.equal_range(item_id);
-      IDMap::iterator proc_iter =
-          std::find_if(item_ids.first, item_ids.second,
-                       MatchSecond<int>(request_tracker_id));
-      DCHECK(proc_iter != item_ids.second);
-
-      // Before removing, determine if no other request trackers refer to the
-      // current item id. If |proc_iter| (the current request tracker) is the
-      // lower bound of request trackers containing the current item id and if
-      // |next_proc_iter| is the upper bound (the first request tracker that
-      // does not), then only one request tracker, the one being removed, refers
-      // to the item id.
-      IDMap::iterator next_proc_iter = proc_iter;
-      ++next_proc_iter;
-      bool last_request_tracker_for_item_id =
-          (proc_iter == item_ids.first && next_proc_iter == item_ids.second);
-      item_id_to_request_tracker_id_.erase(proc_iter);
-
-      if (last_request_tracker_for_item_id) {
-        // The current item id is not referenced by any other request trackers,
-        // so remove it from id_to_item_ and item_to_id_.
-        RemoveInternal(item_id);
-      }
-    }
-    if (request_tracker_ids.first != request_tracker_ids.second)
-      request_tracker_id_to_item_id_.erase(request_tracker_ids.first,
-                                           request_tracker_ids.second);
-  }
-
-  // Bidirectional mapping between items and the request trackers they are
-  // associated with.
-  IDMap request_tracker_id_to_item_id_;
-  IDMap item_id_to_request_tracker_id_;
-  // Bidirectional mappings between items and the item-level identifiers that
-  // have been assigned to them.
-  ItemMap id_to_item_;
-  ReverseItemMap item_to_id_;
-
-  // The ID to assign to the next item stored.
-  int next_item_id_;
-
-  // This lock protects: request_tracker_id_to_item_id_,
-  // item_id_to_request_tracker_id_, id_to_item_, and item_to_id_.
-  base::Lock lock_;
-};
-
-}  // namespace web
-
-#endif  // IOS_WEB_NET_REQUEST_TRACKER_DATA_MEMOIZING_STORE_H_