RFC: use some in-memory state in SimpleCache to quickly cache-miss some CantConditionalize cases

net/disk_cache/simple/simple_backend_impl.h

 // Copyright (c) 2013 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 NET_DISK_CACHE_SIMPLE_SIMPLE_BACKEND_IMPL_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_BACKEND_IMPL_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 102 matching lines @@
   int CalculateSizeOfEntriesBetween(
       base::Time initial_time,
       base::Time end_time,
       const CompletionCallback& callback) override;
   std::unique_ptr<Iterator> CreateIterator() override;
   void GetStats(base::StringPairs* stats) override;
   void OnExternalCacheHit(const std::string& key) override;
   size_t DumpMemoryStats(
       base::trace_event::ProcessMemoryDump* pmd,
       const std::string& parent_absolute_name) const override;
+  uint8_t GetMemoryEntryData(const std::string& key) override;
+  void SetMemoryEntryData(const std::string& key, uint8_t data) override;
 
  private:
   class SimpleIterator;
   friend class SimpleIterator;
 
   using EntryMap = std::unordered_map<uint64_t, SimpleEntryImpl*>;
 
   using InitializeIndexCallback =
       base::Callback<void(base::Time mtime, uint64_t max_size, int result)>;
 
@@ skipping 97 matching lines @@
   // operations to be run at the completion of the Doom.
   std::unordered_map<uint64_t, std::vector<base::Closure>>
       entries_pending_doom_;
 
   net::NetLog* const net_log_;
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_BACKEND_IMPL_H_