Record the tab state during data use

components/data_use_measurement/core/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>
@@ skipping 11 matching lines @@
 #endif
 
 class GURL;
 
 namespace net {
 class URLRequest;
 }
 
 namespace data_use_measurement {
 
+class DataUseAscriber;
 class URLRequestClassifier;
 
 // 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:
   DataUseMeasurement(
+      DataUseAscriber* ascriber,
       std::unique_ptr<URLRequestClassifier> url_request_classifier,
       const metrics::UpdateUsagePrefCallbackType& metrics_data_use_forwarder);
   ~DataUseMeasurement();
 
   // Called before a request is sent.
   void OnBeforeURLRequest(net::URLRequest* request);
 
   // Called right after a redirect response code was received for |request|.
   void OnBeforeRedirect(const net::URLRequest& request,
                         const GURL& new_location);
@@ skipping 14 matching lines @@
 #endif
 
  private:
   friend class DataUseMeasurementTest;
   FRIEND_TEST_ALL_PREFIXES(DataUseMeasurementTest,
                            TimeOfBackgroundDownstreamBytes);
 
   // Specifies that data is received or sent, respectively.
   enum TrafficDirection { DOWNSTREAM, UPSTREAM };
 
+  enum TabState { FOREGROUND, BACKGROUND, UNKNOWN };

[RyanSturm, 2016/12/16 16:26:10]

Is this enum really necessary, you treat it as boolean wherever you use it, so
maybe it is better to pass is_visible or is_in_foreground.

[Raj, 2016/12/16 19:59:10]

Done.

+
   // Returns the current application state (Foreground or Background). It always
   // returns Foreground if Chrome is not running on Android.
   DataUseUserData::AppState CurrentAppState() const;
 
   // Makes the full name of the histogram. It is made from |prefix| and suffix
   // which is made based on network and application status. suffix is a string
   // representing whether the data use was on the send ("Upstream") or receive
   // ("Downstream") path, whether the app was in the "Foreground" or
   // "Background", and whether a "Cellular" or "WiFi" network was use. For
   // example, "Prefix.Upstream.Foreground.Cellular" is a possible output.
@@ skipping 34 matching lines @@
   // DataUse.Services.{Dimensions}. In the second one, services are buckets.
   // |app_state| indicates the app state which can be foreground, background, or
   // unknown.
   void ReportDataUsageServices(
       data_use_measurement::DataUseUserData::ServiceName service,
       TrafficDirection dir,
       DataUseUserData::AppState app_state,
       bool is_connection_cellular,
       int64_t message_size) const;
 
+  // A helper function used to record the app and tab state when data use

[RyanSturm, 2016/12/16 16:26:11]

How about "Records data use histograms split on TrafficDirection, AppState and
TabState."

[Raj, 2016/12/16 19:59:10]

Done.

+  // happens.
+  void RecordTabStateHistogram(TrafficDirection dir,
+                               DataUseUserData::AppState app_state,
+                               TabState tab_state,
+                               int64_t bytes);
+
   // Classifier for identifying if an URL request is user initiated.
   std::unique_ptr<URLRequestClassifier> url_request_classifier_;
 
   // Callback for updating data use prefs.
   // TODO(rajendrant): If a similar mechanism would need be used for components
   // other than metrics, then the better approach would be to refactor this
   // class to support registering arbitrary observers. crbug.com/601185
   metrics::UpdateUsagePrefCallbackType metrics_data_use_forwarder_;
 
+  // DataUseAscriber used to get the attributes of data use. Not owned by

[RyanSturm, 2016/12/16 16:26:11]

I don't think you need to say "Not owned by |this|" since it is a raw pointer.

[Raj, 2016/12/16 19:59:10]

Done.

+  // |this|.
+  DataUseAscriber* ascriber_;
+
 #if defined(OS_ANDROID)
   // Application listener store the last known state of the application in this
   // field.
   base::android::ApplicationState app_state_;
 
   // ApplicationStatusListener used to monitor whether the application is in the
   // foreground or in the background. It is owned by DataUseMeasurement.
   std::unique_ptr<base::android::ApplicationStatusListener> app_listener_;
 
   // Number of bytes received and sent by Chromium as reported by the operating
@@ skipping 14 matching lines @@
   // True if app is in background and first network read has not yet happened.
   bool no_reads_since_background_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(DataUseMeasurement);
 };
 
 }  // namespace data_use_measurement
 
 #endif  // COMPONENTS_DATA_USE_MEASUREMENT_CONTENT_DATA_USE_MEASUREMENT_H_