Refactor the DataUseMeasurement class

components/data_use_measurement/content/data_use_measurement.h

Index: components/data_use_measurement/content/data_use_measurement.h
diff --git a/components/data_use_measurement/content/data_use_measurement.h b/components/data_use_measurement/content/data_use_measurement.h
index cb344fa2b6a7a519301944a3013dbaae5e41104e..6d7ba0aa756e08c19de8547d3404a8b65b2fe095 100644
--- a/components/data_use_measurement/content/data_use_measurement.h
+++ b/components/data_use_measurement/content/data_use_measurement.h
@@ -20,6 +20,8 @@
 #include "base/android/application_status_listener.h"
 #endif
 
+class GURL;
+
 namespace net {
 class URLRequest;
 }
@@ -38,8 +40,11 @@ class 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);
@@ -80,6 +85,9 @@ class DataUseMeasurement {
       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