Bounce all requests off the cache lock after 25ms.

net/http/http_cache.h

 // Copyright (c) 2012 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.
 
 // This file declares a HttpTransactionFactory implementation that can be
 // layered on top of another HttpTransactionFactory to add HTTP caching.  The
 // caching logic follows RFC 7234 (any exceptions are called out in the code).
 //
 // The HttpCache takes a disk_cache::Backend as a parameter, and uses that for
 // the cache storage.
@@ skipping 182 matching lines @@
   // immediately, but they will not be reusable. This is for debugging.
   void CloseAllConnections();
 
   // Close all idle connections. Will close all sockets not in active use.
   void CloseIdleConnections();
 
   // Called whenever an external cache in the system reuses the resource
   // referred to by |url| and |http_method|.
   void OnExternalCacheHit(const GURL& url, const std::string& http_method);
 
-  // Causes all transactions created after this point to effectively bypass
-  // the cache lock whenever there is lock contention.
-  void BypassLockForTest() {
-    bypass_lock_for_test_ = true;
-  }
-
   // Causes all transactions created after this point to generate a failure
   // when attempting to conditionalize a network request.
   void FailConditionalizationForTest() {
     fail_conditionalization_for_test_ = true;
   }
 
   // HttpTransactionFactory implementation:
   int CreateTransaction(RequestPriority priority,
                         scoped_ptr<HttpTransaction>* trans) override;
   HttpCache* GetCache() override;
@@ skipping 184 matching lines @@
   // Processes the backend creation notification.
   void OnBackendCreated(int result, PendingOp* pending_op);
 
   // Variables ----------------------------------------------------------------
 
   NetLog* net_log_;
 
   // Used when lazily constructing the disk_cache_.
   scoped_ptr<BackendFactory> backend_factory_;
   bool building_backend_;
-  bool bypass_lock_for_test_;
   bool fail_conditionalization_for_test_;
 
   Mode mode_;
 
   scoped_ptr<HttpTransactionFactory> network_layer_;
 
   scoped_ptr<disk_cache::Backend> disk_cache_;
 
   scoped_ptr<DiskBasedCertCache> cert_cache_;
 
@@ skipping 12 matching lines @@
   scoped_ptr<base::Clock> clock_;
 
   base::WeakPtrFactory<HttpCache> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpCache);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_CACHE_H_