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

net/disk_cache/simple/simple_backend_impl.cc

 // 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.
 
 #include "net/disk_cache/simple/simple_backend_impl.h"
 
 #include <algorithm>
 #include <cstdlib>
 #include <functional>
 #include <limits>
@@ skipping 558 matching lines @@
 
   size_t size = base::trace_event::EstimateMemoryUsage(index_) +
                 base::trace_event::EstimateMemoryUsage(active_entries_);
   // TODO(xunjieli): crbug.com/669108. Track |entries_pending_doom_| once
   // base::Closure is suppported in memory_usage_estimator.h.
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                   base::trace_event::MemoryAllocatorDump::kUnitsBytes, size);
   return size;
 }
 
+uint8_t SimpleBackendImpl::GetMemoryEntryData(const std::string& key) {
+  const uint64_t entry_hash = simple_util::GetEntryHashKey(key);
+  return index_->GetMemoryEntryData(entry_hash);
+}
+
+void SimpleBackendImpl::SetMemoryEntryData(const std::string& key,
+                                           uint8_t data) {
+  const uint64_t entry_hash = simple_util::GetEntryHashKey(key);
+  index_->SetMemoryEntryData(entry_hash, data);
+}
+
 void SimpleBackendImpl::InitializeIndex(const CompletionCallback& callback,
                                         const DiskStatResult& result) {
   if (result.net_error == net::OK) {
     index_->SetMaxSize(result.max_size);
     index_->Initialize(result.cache_dir_mtime);
   }
   callback.Run(result.net_error);
 }
 
 void SimpleBackendImpl::IndexReadyForDoom(Time initial_time,
@@ skipping 182 matching lines @@
 }
 
 // static
 void SimpleBackendImpl::FlushWorkerPoolForTesting() {
   // We only need to do this if we there is an active task runner.
   if (base::ThreadTaskRunnerHandle::IsSet())
     g_sequenced_worker_pool.Get().FlushForTesting();
 }
 
 }  // namespace disk_cache