Refactor net::BackoffEntry to not require subclassing

components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.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 COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_SERVICE_CLIENT_H_
 #define COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_SERVICE_CLIENT_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
@@ skipping 43 matching lines @@
   // Virtual for testing.
   virtual net::BackoffEntry* GetBackoffEntry();
 
   // Sets a timer to determine when to next refresh the Data Reduction Proxy
   // configuration.
   // Virtual for testing.
   virtual void SetConfigRefreshTimer(const base::TimeDelta& delay);
 
   // Returns the current time.
   // Virtual for testing.
-  virtual base::Time Now() const;
+  virtual base::Time Now();
 
   // Constructs a synthetic response based on |params_|.
   // Virtual for testing.
   virtual std::string ConstructStaticResponse() const;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(DataReductionProxyConfigServiceClientTest,
                            TestConstructStaticResponse);
   friend class TestDataReductionProxyConfigServiceClient;
 
@@ skipping 18 matching lines @@
       config_refresh_timer_;
 
   // Enforce usage on the IO thread.
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(DataReductionProxyConfigServiceClient);
 };
 
 }  // namespace data_reduction_proxy
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_SERVICE_CLIENT_H_