Expose API to store and load data usage stats from UI task runner.

chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.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 CHROME_BROWSER_NET_SPDYPROXY_DATA_REDUCTION_PROXY_CHROME_SETTINGS_H_
 #define CHROME_BROWSER_NET_SPDYPROXY_DATA_REDUCTION_PROXY_CHROME_SETTINGS_H_
 
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_request_options.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 class PrefService;
 
 namespace base {
+class SequencedTaskRunner;
 class SingleThreadTaskRunner;
 }
 
 namespace data_reduction_proxy {
 class DataReductionProxyIOData;
+class DataStore;
 }
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 class PrefService;
 
 // Data reduction proxy settings class suitable for use with a Chrome browser.
 // It is keyed to a browser context.
@@ skipping 19 matching lines @@
   // the UI thread.
   DataReductionProxyChromeSettings();
 
   // Destructs the settings object.
   ~DataReductionProxyChromeSettings() override;
 
   // Overrides KeyedService::Shutdown:
   void Shutdown() override;
 
   // Initialize the settings object with the given io_data, prefs services,
   // request context getter, and task runner.

[jeremyim, 2015/07/13 20:19:40]

Update comment with new params

[Not at Google. Contact bengr, 2015/07/14 16:41:30]

Done.

   void InitDataReductionProxySettings(
       data_reduction_proxy::DataReductionProxyIOData* io_data,
       PrefService* profile_prefs,
       net::URLRequestContextGetter* request_context_getter,
-      const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner);
+      scoped_ptr<data_reduction_proxy::DataStore> store,
+      const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner,
+      const scoped_refptr<base::SequencedTaskRunner>& db_task_runner);
 
   // Gets the client type for the data reduction proxy.
   static data_reduction_proxy::Client GetClient();
 
   // Public for testing.
   void MigrateDataReductionProxyOffProxyPrefs(PrefService* prefs);
 
  private:
   // Helper method for migrating the Data Reduction Proxy away from using the
   // proxy pref. Returns the ProxyPrefMigrationResult value indicating the
   // migration action taken.
   ProxyPrefMigrationResult MigrateDataReductionProxyOffProxyPrefsHelper(
       PrefService* prefs);
 
   DISALLOW_COPY_AND_ASSIGN(DataReductionProxyChromeSettings);
 };
 
 #endif  // CHROME_BROWSER_NET_SPDYPROXY_DATA_REDUCTION_PROXY_CHROME_SETTINGS_H_