Update data reduction proxy statistics prefs less often on desktop

components/data_reduction_proxy/browser/data_reduction_proxy_metrics.h

 // Copyright 2014 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_BROWSER_DATA_REDUCTION_PROXY_METRICS_H_
 #define COMPONENTS_DATA_REDUCTION_PROXY_BROWSER_DATA_REDUCTION_PROXY_METRICS_H_
 
 #include "base/time/time.h"
 
 namespace net {
 class URLRequest;
 }
 
-class PrefService;
+namespace data_reduction_proxy {
 
-namespace data_reduction_proxy {
+class DataReductionProxyStatisticsPrefs;
 
 enum DataReductionProxyRequestType {
   VIA_DATA_REDUCTION_PROXY,  // A request served by the data reduction proxy.
 
   // Below are reasons why a request is not served by the enabled data reduction
   // proxy. Off-the-record profile data is not counted in all cases.
   HTTPS,  // An https request.
   SHORT_BYPASS,  // The client is bypassed by the proxy for a short time.
   LONG_BYPASS,  // The client is bypassed by the proxy for a long time (due
                 // to country bypass policy, for example).
@@ skipping 12 matching lines @@
     int64 original_content_length,
     int64 received_content_length);
 
 // This is only exposed for testing. It is normally called by
 // UpdateContentLengthPrefs.
 void UpdateContentLengthPrefsForDataReductionProxy(
     int received_content_length,
     int original_content_length,
     bool with_data_reduction_proxy_enabled,
     DataReductionProxyRequestType request_type,
-    base::Time now, PrefService* prefs);
+    base::Time now,
+    DataReductionProxyStatisticsPrefs* prefs);
 
 // Records daily data savings statistics to prefs and reports data savings UMA.
 void UpdateContentLengthPrefs(
     int received_content_length,
     int original_content_length,
     bool with_data_reduction_proxy_enabled,
     DataReductionProxyRequestType request_type,
-    PrefService* prefs);
+    DataReductionProxyStatisticsPrefs* prefs);
 
 }  // namespace data_reduction_proxy
 
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_BROWSER_DATA_REDUCTION_PROXY_METRICS_H_