Refactor the DataUseMeasurement class

components/data_use_measurement/content/data_use_measurement.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_USE_MEASUREMENT_CONTENT_DATA_USE_MEASUREMENT_H_
 #define COMPONENTS_DATA_USE_MEASUREMENT_CONTENT_DATA_USE_MEASUREMENT_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "components/data_use_measurement/core/data_use_user_data.h"
 #include "components/metrics/data_use_tracker.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/application_status_listener.h"
 #endif
 
+class GURL;
+
 namespace net {
 class URLRequest;
 }
 
 namespace data_use_measurement {
 
 // Records the data use of user traffic and various services in UMA histograms.
 // The UMA is broken down by network technology used (Wi-Fi vs cellular). On
 // Android, the UMA is further broken down by whether the application was in the
 // background or foreground during the request.
 // TODO(amohammadkhan): Complete the layered architecture.
 // http://crbug.com/527460
 class DataUseMeasurement {
  public:
   explicit DataUseMeasurement(
       const metrics::UpdateUsagePrefCallbackType& metrics_data_use_forwarder);
   ~DataUseMeasurement();
 
-  // Records the data use of the |request|, thus |request| must be non-null.
-  void ReportDataUseUMA(const net::URLRequest* request) const;
+  // Called right after a redirect response code was received for |request|.
+  void OnBeforeRedirect(net::URLRequest* request, const GURL& new_location);

[sclittle, 2016/08/23 00:49:28]

nit: could you pass in |request| by const ref? Same with OnCompleted and
ReportDataUseUMA.

[tbansal1, 2016/08/23 00:58:51]

Done.

+
+  // Indicates that |request| has been completed or failed.
+  void OnCompleted(net::URLRequest* request, bool started);
 
   // Returns true if the URLRequest |request| is initiated by user traffic.
   static bool IsUserInitiatedRequest(const net::URLRequest* request);
 
 #if defined(OS_ANDROID)
   // This function should just be used for testing purposes. A change in
   // application state can be simulated by calling this function.
   void OnApplicationStateChangeForTesting(
       base::android::ApplicationState application_state);
 #endif
@@ skipping 20 matching lines @@
                                TrafficDirection dir,
                                bool is_connection_cellular) const;
 
 #if defined(OS_ANDROID)
   // Called whenever the application transitions from foreground to background
   // and vice versa.
   void OnApplicationStateChange(
       base::android::ApplicationState application_state);
 #endif
 
+  // Records the data use of the |request|, thus |request| must be non-null.
+  void ReportDataUseUMA(const net::URLRequest* request) const;
+
   // A helper function used to record data use of services. It gets the size of
   // exchanged message, its direction (which is upstream or downstream) and
   // reports to two histogram groups. DataUse.MessageSize.ServiceName and
   // DataUse.Services.{Dimensions}. In the second one, services are buckets.
   void ReportDataUsageServices(
       data_use_measurement::DataUseUserData::ServiceName service,
       TrafficDirection dir,
       bool is_connection_cellular,
       int64_t message_size) const;
 
@@ skipping 12 matching lines @@
   // foreground or in the background. It is owned by DataUseMeasurement.
   std::unique_ptr<base::android::ApplicationStatusListener> app_listener_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(DataUseMeasurement);
 };
 
 }  // namespace data_use_measurement
 
 #endif  // COMPONENTS_DATA_USE_MEASUREMENT_CONTENT_DATA_USE_MEASUREMENT_H_